The Strongest Frame in the World of Internals

The 'Critical Mass' Hip Belt

A Revolutionary Shoulder Pad System

Critical Mass Pelvic/Lumbar Pad


The Strongest Frame in the Industry - Bayonet Frame U.S. Patent # 5292043

Q-Bayonet and P&G Bayonet: Scroll to bottom to see the latest.

A pack can have a great hip belt and shoulder pads, but without a solid frame, it does not matter.  In a world of internals that are too soft, the 7075-T6 Critical Mass frame and Sarc Series frames can really handle the load.  It is the only frame system, internal or external that can do all of the following:

  • Maintain its shape through the abuses of backpacking.
  • Sitting on your pack or dropping it are examples of abuse it can sustain.
  • Be reshaped to better comply to your anatomy without
    losing any of the new shape in the short or long term. In most cases longer term experience is required to find the perfect shape. Your 7075-T6 stays are always ready for reshaping!
  • Provide more real headroom that is also moldable/adjustable.
  • Carry whatever type of load required up to 120 lb. loads at a high performance level:

  • The load on a CM frame feels lighter than it really is - same for the lighter weight Sarc Series where 2 to 4 oz. frame set weights are common - for loads from 20 to 60 lbs.
  • Shorten and fold out of the way for side trips. The
    patented 2-piece, and 4 piece 7075-T6 Bayonet frame is stronger
    than single piece frames.
  • The CM frame and Sarc Series frame sets do not impact the rear of your pelvis.
    It actually straddles the sacrum and eliminates much
    of the rigid pendulum force vector of many frames that must be padded by excessively thick lumbar pads.
  • Our Criteria for a Pack Frame:
    Strength enough to maintain its shape against the pressure of a heavy load and strength enough to resist collapse entirely on its own.  An extra margin of strength is necessary to withstand abuse.  Setting a pack down hard with a heavy load should not bend the frame.  We achieve all this, without an increase in weight, by using the remarkable aluminum alloy 7075-T6. CM frame below:

    Comparison with Other Frames

  • A single stay from the SARC frame (7075-T6) system can support your entire load.  Two stays easily control the heaviest loads. 
  • Single stay pack systems require frame-sheets and/or cross-members of some type. Twin stays ultimately are more effective. Even carbon fiber cannot touch the overall toughness of 7075-T6 in the dimensions we use. 7075-T6 can be reshaped and will hold its shape through use. Carbon frames cannot be remolded.
  • We offer many different dimensions of 7075-T6 frame stock (from light-weight to super-heavy duty) to match your backpacking load requirement.
  • 6061-T6 alloy, used in much of the mass market backpack industry, does not know when to stop bending.  This most commonly used alloy and dimension is completely unsuitable for large capacity internal frames where strength and durability are important and most companies anything nearly this strong.  Nevertheless, it is found in more packs than any other alloy!
  • Below: The P&G Bayonet frame extension system. They add length to the frame and in the process the shoulder harness converts from our simple guide harness to the Bypass Harness. The Bayonets can be used to stabilize a bigger heavier load without adding the Bypass straps as well. These bayonet stays are just under 12" long x 1/2" x 1/8" and weigh 2.4 oz / set. They overlap the lower main frame for half of the length of the bayonets and make adjusting headroom a snap.
  • Q-Bayonet - At the other end of the Sarc main stays, the lower ends, are a new swiveling bayonet that adjust to accomodate different weight loads. When the bayonet is turned up and the frame is shortened, the pack bag compresses around it. These have been in production for almost 4years and give a full range of adjustability for the packs owner.