To prevent the body of the pack from swinging side to side, a shock absorbing cord connects it to either side of the harness on the shoulders, and webbing straps pull in under the arms. All of these can be loosened or tightened for the right fit and feel while on the go.

The harness itself is based on a running vest design with flat and wide straps that follow the contours of your chest, moving with it without any constriction. So essentially you have a running vest on the front, and pack on the back. Unusual, yes, but it works well.

Aside from this impressive carrying system, OMM have included a full bottle holder on the right hand shoulder strap and a smaller, stretchier phone/soft water bottle carrying pocket on the left side. Access to the main compartment is via the zip that spans across the top of the pack and there’s one smaller top pocket to keep smaller items such as power gels and a mobile phone.

Two separate fabrics have been used at the back, including a 60D ultra-high-molecular-weight waterproof polyethylene on the sides, top and bottom, and an extremely lightweight and thin waterproof material at the front.

You’d need to be a real minimalist and have some very lightweight camping gear to be able to use this for the Original Mountain Marathon itself, but it’s still possible. However, we’d say it’s perhaps better-suited to huge days in the mountains where you need some emergency kit and plenty of food, but also have a bed to get back to at the end. For something like the Berghaus Dragon’s Back, where runners go for five days but have a basecamp ready and waiting for them each evening, this would be absolutely ideal.

Tester’s Verdict

Jordan Tiernan, Outdoors Magic Staff Writer

“Stability has been the focus of the Phantom 20L and stability is what OMM have achieved – even when the pack is fully loaded, as I’ve found out whilst using it for both running and cycling.

“It’s worth making sure to carefully adjust the fit to suit each load you’re carrying and to spread its weight equally across the anchor points. Once I’ve got this right it’ll carry better than any other trail-running pack I’ve tried.

“That being said, this pack suffers from the usual durability issues that we’ve come to expect from trail-running gear. If you tend to haphazardly toss your pack face down onto rocks, then expect the extremely thin waterproof fabric on the front of it to get worn or torn. This can of course be avoided by just taking a bit of care.”