Bolt Assembly Stainless Steel, 3″, 2-washers, bolt, nut. All stainless steel 3″ bolt, two bent washers and vibration proof lock nut. Our square frame kennels are bolted together using a stainless steel bolt assembly that is designed to wrap around each frame for increased strength, unlike round tube framed kennels which use a round clamp system which often become loose and rotate. Our bolt assembly includes all stainless steel bolts and vibration proof stainless steel ny-lock nuts. We chose this design due to our own experience with brackets that loosen and fail.