This is my second kit from USRockets, and I've been really happy with it. Good, strong materials, 54mm mount, very stable design. The Megaroc has a 4" diameter cardboard airframe and stands about 8' tall. The airframe and fins are reinforced with 2 layers of 4oz fiberglass, making it a very tough rocket. Its size makes it great for flying on motors as small as an H, up to a K and possibly L. This picture was taken at its first flight in Millican, Oregon, the Fall of 1997, before the paint job was complete. Update - 07/17/01 The Megaroc was retired after a shred in '99. See below...