The Critical Mass Pelvic/Lumbar Pad
Of all the features of the SARC packs, the lumbar/sacrum pad is the most uniquely evolved.  Since we believe so strongly in full circling hip belts, the lumbar/sacrum pad was developed separately.  Today after 30 plus years of development and refinement, the SARC lumbar/sacrum pad can handle heavier loads than those of any other pack.

Unlike systems of other internal frame packs, the SARC lumbar/sacrum pad does not ride between you and the frame stays.  The 2 layer pad sits between you and the sleeping stuff bag, actually bypassing the frame stays.  Over the years, we discovered that instead of building a padded wall between you and the frame, it was better to widen the space separating the stays and let the lumbar/sacrum pad ride directly on the sleeping bag stuff sack.  This creates a reservoir of padding instead of a hard frame behind.  Two sleeping bag compression straps hold the sleeping bag stuff sack forward against the frame in order to control the density of the reservoir.  Simply by adjusting the straps, you control how firm, or how much the pad sinks into the sleeping bag.





The Critical Mass System pad has velcro wings that can push the pad forward and be locked into place.  The straps around the sleeping bag stuff sack act as a backup for the heaviest loads (75 to 125 lb.).  You can make density adjustments to the pad by subtracting layers or by adding different densities of foam.  Not only can you replace foam layers, the entire pad envelope can be replaced after heavy use.  The lightweight pad envelope is made of 200 denier nylon and is protected inside the pack.