Weighing less than a kilo the Osprey Exos Pro 55 (Eja Pro55 for women) really deserves the description ultralight. This doesn’t mean it’s a minimalist pack though. It has all the features of the other packs reviewed, just made with lighter, thinner materials. In fact, it’s very similar in design to the heavier Exos 58. This backpacking pack has appeared in our guide to the best backpacking packs

Price: $290 | £230 (available from Ellis Brigham)

Weight: 950g (S/M) | Capacity: S/M 55 litres, L/XL 58 litres | Materials: 100D Nylon x 200D UHMWPE (ultra-high-molecular-weight polyethylene) ripstop | Closure: detachable lid, buck | Back: wire frame, tensioned mesh panel | Hipbelt: padded, shaped | Pockets: zipped lid, 2 stretch mesh side, stretch mesh/fabric front, zipped hipbelt, zipped open top hipbelt | Features: side compression straps, ice axe/trekking pole straps, inner hydration sleeve, front and lid attachment loops | Sizes: men S/M, L/XL, women (Eja Pro) WXS/S, WM/L | Women’s Version: Eja Pro

This is the only pack I tested with a curved back that’s held away from the body by a tensioned mesh panel. This greatly reduces sweat build-up. Perforated foam on the shoulder straps and hipbelt also aids ventilation. The shoulder straps are well-padded, the hipbelt slightly less so. Without giving a maximum weight Osprey says the Exos Pro is for “lighter loads”. I found it comfortable with 12kg.

The pack comes in two men’s and two women’s sizes and has a ladder system that allows up to 10cm of adjustment in each size, which gives more options for fit than the other packs I tested.

The fabric is bluesign approved and has a non-PFC DWR treatment. It’s quite thin but being nylon reinforced with tough polyethylene should prove durable. There are two closure options, a removable floating lid and a fixed flap. Removing the lid saves 80 grams of weight and reduces the volume by 9 litres. The flap then covers the contents and clips onto the same front buckles as the lid. It’s not removable and when the lid is used it just hangs down inside the pack.

The six pockets of the Osprey Exos Pro 55 are roomy. The side ones have top and side access so you can pull out a water bottle while wearing the pack. The front pocket is solid fabric with mesh side panels. It doesn’t stretch as much as all mesh ones but should prove harder wearing. If you need to attach items to the outside there are double compression straps on each side and four lash loops on the lid and ten on the front.

For backpackers looking to cut weight, the Osprey Exos Pro 55/Eja Pro 55 is excellent.

TheOsprey Exos Pro 55 comes recommended by our Gear Editor. To read the other pack reviews in this test head to The Great Outdoors’ best backpacking packs.

Chris Townsend headshot

Tested by Chris Townsend

Chris tested these packs on trips in the Cairngorms with plenty of ascent and rough terrain in snow, rain, high winds and occasional sunshine in the autumn, winter, and early spring. Chris is 5’8 with a long back (49.5cm). All weights were measured on Chris’s digital scales.