I acquired my Mainstruck (prototype) box from Geary Schindel at the 1993 Speleofest.
The Mainstruck prototype is 76 mm. long, 151 mm. wide, 60 mm. high, and weighs 272 g. It is a double channel chest box built out of the same carbon fiber composite used on the B-2 Stealth bomber. The back plate has 45 mm. tall vertical slots for attaching the box to a chest harness. The rollers and pins were taken from Simmons Rollers.
The Quick Release pins are stamped with "AVIBANK PUSH" and "55207XXX."
This is a lightweight box, but I feel that it is too bulky. As a prototype, it proves that carbon fiber is a good material to make a box from, although the labor involved in the prototype was fairly high.