The Osprey Eja Pro 55 Backpack is a women’s-specific lightweight backpack that has an adjustable torso length and a ventilated, tensioned back panel. New for 2023, it’s a cut-down version of the popular Osprey Eja 58 that’s 12 oz lighter in weight with a few minor design changes. While it carries loads up to 30 lbs very well, the use of thinner fabrics means it will be less abrasion resistant than the Eja 58.
Specs at a Glance
- Weight: 1lb 14.8 oz, Size XS/S
- Strippable Top Lid Weight: 2.6 oz
- Volume: 52 Liters (XS/S) Note – the size M/L is 55 liters
- Closure: Top lid
- Adjustable Torso Length: Yes
- Ventilated: Yes
- Hydration compatible: See below
- Pockets: 6 plus the main compartment
- Frame: Internal aluminum perimeter frame
- Torso: XS/S 13-17”, S/M 16-20”
- Waist: XS/S 26-45”, S/M 28-50”
- Bear Canister Compatibility: BV500 or Garcia Backpacker’s Cache fit horizontally or vertically in the main compartment. They can also be held in place under the floating top lid pocket.
- Materials: 100D Nylon x 200D UHMWPE ripstop w/ DWR treatments made without PFAS
- Maximum load: 30 lbs
Who is the Eja Pro 55 For?
The Osprey Eja Pro 55 is a great pack for anyone looking for a multi-day ventilated backpack with a women’s fit with a ventilated suspended mesh frame. Instead of the rolltop closure common on most ultralight backpacks, it has a top lid pocket (very handy) and many of the external attachment features found on conventional multi-day backpacks. There really are not many ultralight backpack options with a women’s-specific fit, so if that is what you are looking for, this pack is worth checking out.
While you can switch to a more minimalist roll-top backpack like the ventilated Women’s Zpacks Arc Haul Ultra 60, doing so can require a pretty big change in how you pack and interact with your backpack during the day. Whichever way you choose to go, Osprey and Zpacks are still the only pack manufacturers to offer ultralight, ventilated, and adjustable torso-length backpacks designed for women. What’s up with that guys?
How is the Eja Pro 55 different than the Eja 58?
The Eja Pro 55 is a lighter-weight version of the original Eja 58, and is different in the following ways.
- It is 12 oz lighter weight than the Eja 58 (may vary depending on sizing).
- Does not have a second pocket under the top lid.
- Does not have separate sleeping pad straps on the front of the pack.
- The front stretch pocket has fabric loops along the sides that can be used to hang gear.
- The front stretch pocket has less mesh and more solid fabric for better durability.
- The left-hand hip belt pocket is open and not zippered.
- The adjustable torso length is secured using small dowels instead of larger plastic discs.
- There is a silicone print at the base of the suspended mesh to prevent slippage.
- The sternum strap only has three positions instead of a sliding rail adjustment.
- The shoulder straps are less padded.
- The shoulder straps have inadequate hydration hose keepers (see below).
- There’s no stow-on-the-go trekking pole holder.
- Uses thinner (200d) fabric in high-wear areas.
Backpack Storage and Organization
The Osprey Eja Pro 55 is very different from most ultralight backpacks because it’s configured with a floating top lid instead of a dry-bag style roll top. With a single large top zippered pocket (with key fob), the floating lid lets you sandwich extra gear between the lid and the top of the pack’s main compartment so you can carry extra equipment like bear canisters, foam pads, or tent bodies that won’t fit inside your pack. The top pocket also provides handy access to hats, gloves, snacks, and navigation gear and is indispensable for cold-weather use.
If you don’t need the top lid on the Eja Pro 55, you can remove it to save gear weight. This reduces the weight of a small/medium Eja Pro 55 by 2.6 ounces bringing it down to a respectable 28.4 oz (1 lb 12.4 oz).
There’s a nylon flap under the top lid that is permanently attached to the pack, what Osprey calls a FlapJacket, that covers the drawstring opening of the main compartment. When you remove the top lid, the FlapJacket is used to protect the main compartment from the rain in its stead. The rear of the FlapJacket clips into the same rear straps and buckles used by the top lid so you’re not left with any extra straps or buckles to get in the way. When it’s not needed you can stuff it into the main compartment or into the internal hydration pocket. However, the FlapJacket should not be considered a weather-tight cover. Since the pack is not advertised as waterproof, you would probably be using a pack liner, so this might not be an issue for you.
While the Eja Pro 55 also has good open storage in the form of side and front pockets, the main compartment is where the bulk of this pack’s capacity is. With over 3350 cubic inches of room, you can put a ton of gear and food inside. Being a mainstream backpack manufacturer, Osprey only counts covered and zippered storage when they calculate backpack volume. If you are comparing the volume of the Eja Pro 55 with a pack from a cottage backpack maker, be aware that they often add in open and closed pocket volumes so the Eja Pro 55 will feel quite a bit larger and hold considerably more gear.
While the main compartment curves inward to accommodate the shape of the ventilated frame near its base, the main compartment is so large that the pack is still easy to pack. Still, because it is ventilated, you’ll want to position the heaviest items as close to your back and hips as possible. With the exception of a hydration pocket, hang loop, and top compression strap, there’s nothing inside the Eja Pro 55 main compartment like a sleeping bag compartment to break up the seemingly cavernous space. Still, it’s easy to see inside the main compartment because lightly colored fabric panels help channel light to the pack’s interior. I’d still recommend packing the Eja Pro 55 with a pack liner for moisture/rain protection (See Five Ultralight Pack Liners Compared.)
There is a sleeve inside the pack to hold a hydration bladder. However, the mechanism to clip in the hydration bladder seems to be only designed for Osprey hydration bladders and is not universal for others. If it’s not compatible with your reservoir, you can let it fall to the bottom of the sleeve or use a small carabiner to keep it up higher.
Osprey included hipbelt pockets on the Eja Pro 55 but they’re slightly different than those on the current Eja 58. The left-hand pocket is now open on top and doesn’t have a zipper. I thought I’d hate that, but it’s actually pretty useful for stuffing trash into. The right-hand pocket is still zippered and large enough to fit an iPhone X into along with some snack bars.
But the pockets are sewn onto the hipbelt in such a way that the back of the pocket has to be able to curve when it wraps around your hips…which is a good way to break a SmartPhone screen. I’d advise against putting anything similarly oversized and inflexible into them.
The hip belt wings on the Eja Pro 52 are shorter than you might find on a comparable pack. This means that the pockets are smaller and further back than you might expect. Regardless, the hip belt is just as comfortable for me as other packs I have with longer belt wings.
In addition to the main compartment, the Eja Pro 55 has two stretch-side mesh pockets that can be used to store water bottles. Each pocket is reinforced with solid fabric on the bottom for better durability and has a holster-style opening cut in front, which lets you position bottles sideways so you can pull them out and replace them when on the move.
Osprey Eja Pro 55 Backpack
Though you can put a 1 liter Nalgene in the pocket holster style when not wearing the pack, it is tough to do when the pack is full, and nearly impossible while wearing the full pack. The pockets are quite tall but if you put bottles in vertically, it is not possible to get them into or out while wearing the pack. A smaller diameter 1-liter bottle will fit in the holster opening but will stick out of the pocket far enough to be in the way of your arms. However, a shorter, small-diameter bottle works fine here. I also found the holster opening handy for my snack bottle and could easily get it into and out of the pocket while wearing the pack.
I initially thought the top of the front stuff stretch pocket would be too loose to be secure, but once the pack is fully loaded, this does not seem to be a problem. The fabric on the back of the stretch pocket is an improvement over pockets with only stretch mesh and makes the pocket more durable.
Backpack Frame and Suspension
The Osprey Eja Pro 55 is a ventilated suspended mesh-style backpack. Breathable mesh is suspended in front of the back panel creating a ventilated space behind your back that’s designed to evaporate sweat before it can soak your shirt. The mesh is tightly stretched across the 360-degree aluminum frame which also serves to anchor the hip belt and load lifters. The aluminum frame on the Eja Pro 55 is what “makes” this pack. It’s super lightweight and stiff, providing great load transfer to the hips, so you can load up this pack and still get a very comfortable carry. The carry is actually quite amazing, even with a full load.
This Eja Pro 55 also has an adjustable torso length with 4″ of adjustability that is very lightweight and simple to use. This is a huge benefit for new backpackers who have less experience sizing and fitting a new backpack. You can lengthen or shorten the torso length, the distance between your hip bones and your C7 vertebra, by moving the shoulder strap harness up or down since the position of the hip belt is fixed. This is done using a simple dowel and ladder system which slides up and down along the track on the back of the backpack. I found the system easy to use, perhaps even more so than a Velcro system (such as those favored by Gregory).
However, the padded portion of the shoulder straps is a little too short. If you prefer to wear a sleeveless upper body garment, you may experience some chafing from the shoulder strap buckle where the webbing attaches to the padded strap. I found that by wearing short sleeves I was able to avoid this problem. Other than this, I find the shoulder straps to be comfortable.
The shoulder straps and hipbelt are both covered with a stretchy mesh fabric that is soft and helps wick moisture to prevent rubbing and chafing. The shoulder straps are lightly padded and have one elastic hydration hose keeper strap on the front. However, while the shoulder straps are comfortable, you’ll be somewhat challenged to attach accessory pockets to them, something that is increasingly popular with backpackers and day hikers alike. The same can be said for the lightly padded hip belt.
Unlike the Eja 58, the sternum strap on the Eja Pro 55 can only be positioned in three locations. To adjust, you need to push the plastic buckles through small cord loops that are barely big enough. It takes a couple of minutes of fiddling to get these through, but fortunately, you only need to do to it once.
For hydration reservoir users, I like to use a hydration system and was disappointed that the stock method for securing the hose to the shoulder straps is inadequate. There is a very tight elastic at the top of the shoulder strap that is very hard to get a hose through. It also holds the hose too high up on the strap which causes it to flop around while hiking. I put an elastic on the shoulder strap which is an acceptable solution to this problem. It would have been a simple matter for Osprey to attach a couple of elastic hose keepers further down on the shoulder straps and the additional weight would be imperceptible. Or they could have used the magnetic system they use on some of their other packs.
The Eja Pro 55 comes in two sizes (XS/S 13-17”), S/M (16-20”) in terms of torso length The hip belt sizes are slightly different, going a good 5” larger in the bigger size (XS/S 26-45”, S/M 28-50”).
External Attachment and Compression System
The Osprey Eja Pro 55 has two compression straps on each side of the pack. The top strap is anchored on at the top corner of the front stretch pocket and runs to the frame just below the front load lifter, while the bottom strap is configured as a Z crisscrossing over the side water bottle pocket before attaching to the back of the hip belt pocket I’m not a huge fan of the Z-style threading pattern because I think it makes it difficult to strap bulky gear like snowshoes or a folding pad to the side of a pack. I find two horizontal-side compression straps to be optimal instead.
But one thing that’s missing from Eja Pro 55, but is provided on the Eja 58, is a pair of sleeping bag straps for attaching a folding foam pad, like a NEMO Switchback or a Thermarest Zlite pad to the bottom of the pack below the front stretch pocket. This is very difficult to do with the lower Z-Style side compression straps because they’re not long enough to easily fit over one of these folding pads. You can do it, but it requires a lot of elbow grease and makes it very difficult to put anything into the front stretch pocket because the pad is tightly compressed against the pack. I’d recommend rigging up your own elastic cord loops for attaching a pad to the gear loops running alongside the front stretch pocket instead.
But don’t let the Z-style straps (which are removable by design) deter you from rigging up two horizontal compression straps instead. One of the great things about the Eja Pro 55 is the distribution of gear loops around the perimeter pockets, the pack bag seams, and even the top lid, making it easy to rig up your own custom compression system with an extra cord lock and some guyline or a piece of webbing. If I used the Eja Pro 55 regularly, I’d probably remove the side compression straps and replace them with my own cord and cord locks.
- Great weight-to-capacity ratio. Just under 2 lbs for 55 L and hauling up to 30 lbs.
- Carries well and comfortably
- A Bear canister will fit inside the pack or on top, under the floating top lid
- Great load transfer and control from the lightweight perimeter frame
- Nice colors and styling
- Easy to dial in the fit with an adjustable torso and sternum strap
- Abundant external attachment points
- Ventilated back panel helps reduce back sweat
- Does not readily accept accessory pockets to shoulder straps or hip belt
- Can’t access tall items in the side pockets while wearing the pack
- Z-style side compression straps are not as easy to use for gear storage as simple compression straps. They also make accessing side pocket items more difficult if you have them pulled tight.
- No easy, existing solution for attaching a sleeping pad to the bottom or back of the pack.
- Inadequate attachment on the shoulder straps for a hydration hose, even though the pack is hydration bladder compatible.
- Possible chafing on arms from the shoulder strap buckles.
Comparable Ventilated (Suspended Mesh) Backpacks
There are not a lot of options out there for ventilated backpacks in women’s sizing and fit that weigh under 2 lbs. I have a Gregory Facet 55 which is probably one of the closest competitors at about a half pound more. For me, the areas where Eja Pro 55 shines are the weight and the adjustable torso length. The Facet has bigger hip belt pockets, an attachment for the hydration hose, and straps that work better for exterior pad attachment. It comes down to which features are most important to you.
The Osprey Eja Pro 55 Backpack is a women’s specific top-loading backpack with an adjustable length torso that makes it easy to dial in the fit. Weighing just under 2 lbs, it has a reinforced perimeter-style aluminum frame and ventilated suspension that carries loads up to 30 lbs easily. It is a great choice if you are looking for a traditional, yet lightweight multiday backpack. I find it handles loads with comfort, which is primarily what you want in a backpack. Coming in just slightly under 2 lbs, the Eja 55 Pro is a solid choice for anyone looking for a lightweight pack with a top lid pocket.
My number one complaint with the Eja Pro 55 is the lack of a good solution for keeping a hydration hose under control. It would have been easy for Osprey to incorporate a better method as they have done on other packs. I also I dislike using the Z-style compression straps for a pad or other bulky item. You can make it work, but then the straps may be very tight over the side pocket, making it more difficult to use. However, I’ve yet to find the perfect pack that does everything I want just the way I like it, you must expect to make some compromises. It was not hard to adjust the Eja Pro 55 to my liking or change my methods to work with the pack. The comfort and weight savings are worth a little fiddling.
Disclosure: Osprey donated a backpack for review
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