What i received was, i suspect, a returned product that was missing essential pieces. - SB Tactical SBA4 Brace Complete Kit for Shotgun Firearm

the product box did not contain either the hardware necessary for installation or the "Castle Nut" which goes on the buffer tube. I phoned and got the answer that I could return it and get a replacement, but that they were way backlogged and it would take a long time. The missing pieces are not terribly exotic so I will locally source them and save the grief of possibly getting another incomplete kit in return. I think somebody owes me at least a "Castle Nut". the bolts should be easier. The main component parts seem well designed and I suspect will work fine once I've sourced the missing hardware.