As described in the title and here are the finer details:
Webbing: A-A-55301 Type III (breaking strain is 453.5kg direct pull).
Fabrics: 500d and 1000d Cordura (solution dyed), 4mm Airmesh
Foam: Hip Pad – 2.5mm thick PE35 closed cell. Harness – Dual density EVA30/EVA 90
Fittings: All fittings are ITW Ghillietex aramid with NIR properties.
Thread: A-A-59826 T-90 nylon bonded thread.
The hip pad is thick, 1 1/2 times as thick as the issue hip pad. It is shaped to support your lower back and rounded on the ends to survive the hiding it going to receive better than a square edge would. It secures to the frame with 3" Webbing for the Alice slots and 2 x 1" webbing with removable ladder locs and triglides. There are 2″ ladderlocs on the sides to enable a “gut belt” to be fitted.
The biggest thing you have to remember about the Alice pack was it was never designed to be worn on it’s own or with a vest. It was designed to be used with a belt rig that it could sit on which would act as a hip belt like you see on the gucci civvy packs. It was built at the end of a jungle war and offered the airflow that modern packs with frame bars/sheets that hug your back do not.
The straps are dual density foam, the PE30 is soft and has good memory meaning it wont compress and then stay compressed. The PE30 is meant to provide as much comfort as we can whilst supporting weights of 30-40kg directly on the shoulders. The EVA90 is the load bearing portion of the foam, it is thick and dense and makes the straps keep their shape and more importantly spreads the load across the shoulder as opposed to onto the center webbing strap as a lot of other straps do. The feel very stiff and wont flop around as much as other straps you are used to will, this is intentional.
The shoulder strap panel is one piece of 500d Cordura with Airmesh backing. At the base where the Snap Dragon buckle (image shows QR buckle) is mounted the under side is reinforced with 2″ A-A-55301 webbing. Two 42 stitch bartacks spaced 1.5cm apart are placed through the vertical webbing strap for the Snap Dragon buckle to then be fitted. This provides an extremely solid mounting point. Each strap has an adjustable sternum slider, a D ring for mounting radio handsets or routing hydration cables and a triglide that is mounted to a non adjustable section of webbing. This triglide is used to adjust the strap that connects with the uppermost mounting point and allows you to fine tune the way the weight is carried.
Each shoulder strap is mounted to a central yoke panel. This was done as making the harness one piece was extremely difficult, time consuming and hard to maintain consistency of product. Any seam placed in something like a harness carrying this much weight is a potential point of failure and we have mitigated this by using a 4cm internal seam which is sewn 3 times and then has three 42 stitch bartacks placed in it centrally and each side.
There will be a light change on future versions where the join will be vertical as opposed to horizontal and this will be covered by 2″ webbing with a sewn through box to secure it akin to the one you see on the hip pad.
The upper and lower attachment points are a choke hitch of webbing which has 3 spaced bartacks similar to an anchor point used for rappelling.
The main load is carried on the two vertical straps which interface between the yoke panel and the two slots at the base of the frame. The harness is kept in place with two horizontal stabilizer straps which envelop the frame and stop the side to side play. This also means and acceptable variation in adjustment can be achieved catering to users of different height. The harness is meant to wrap from the base of your shoulder blades over your shoulder and then down across the front under your arms. Use of the sternum strap is highly recommended as it will lock the shoulder straps in and stop them from being able to slide towards the edges of your shoulders.