For attaching stuff to paintball markers rails. Made it heavy duty cause others I found are too weak and break. this is meant to be abs-glued to handle/object you want on paintball marker. ( dont glue this to the paintball marker ) Tested in the field, it is tough. Note : If you need to put a bolt into this you will need to drill the hole out. use the partial holes as a guide. and you will have to file the insides of the pit-grooves alittle to fit. Mine fits so snug I dont use a bolt.