The way it was on the rifle I bought it on was you remove the grip and trigger guard
and this thing goes in it's place. It has a hole in it for the spring and detent, just like
the standard AR grip. The set screw in the upper side of the grip is to adjust the play
in the trigger to actuator pins and the pins have rollers on them so there is no wear
marks on your trigger. If adjusted right when you pull the trigger, the bottom pin works,
and when you push, the top pin works. So, yes it would be a bump fire type of thing,
and when I got it, I couldn't get but three to five rounds at the most to fire so I used
it as a pull only trigger until I could get the standard parts to relpace it. IIRC I didn't
even close my bolt until I was ready to fire because if it was adjusted snug enough to
work right, you could fire the weapon putting your hand in the actuator arm. I am also
curious as it has no markings as to who made it or when, who marketed them and how
much did they go for. I asked the dealer at the fun show about the one he had on a
Mini-14, and he told me it was a winter trigger, so I know he didn't know anything on
them either. I will try to get a good pic of it installed.