This invention is directly from "Bump Fire" the old "hook your thumb to your belt loop, push your rifle forward with your weak hand, place thumb in trigger and hook to belt loop"... Guys be careful doing this. Also, big draw back is you really don't want to hold the pistol grip when doing this "Bump Fire", so you really can't control your weapon. It can be done on a 22LR, seen it and done it. I don't recommend doing this nor do I support the Slide Fire. I give them an "A" for effort and design, but an "F" for major safety issues... Full auto has not place on the range, only in battle and the M&P 15/22 by many, is already considered like a toy, which it is NOT! All we need is one wacko using this in a crime and watch the government really crack down on the M&P 15/22 or rifles in general. Something WE DON'T WANT FOR SURE. AGAIN just my opinion guys...