Muzzy's have a hook on the bottom of the blade that locks it the body. The muzzy tip also threads on to theend of thebody holding the top end together. I have had a blade hit the back of another one in a target and not come loose from the body.

i shoot muzzy's.... but have never seen a broadhead named innerloc. must be a inferior design with inferior metal?

IMO the Muzzy Broadhead design is one of if not the toughest/most durableout there. Neither head is made to be shot at an impenetrable object though. Never had a problem using the innerloc on deer.

Do you even have to ask?

Muzzy are really tough. I missed game and found my arrow stuck in a rock , yes a rock. The muzzy 3 blade (100 grain) just shoved straight back into my arrow. And I think I may of even salvaged some of the muzzy's parts for later.