I have one of the two bladed Selector's. It has a standard blade desighned like a 110 with the nail nick on the proper side, and works as a slip lock. The second blade is the one that can be changed, and has the back lock. To put a nail nick in that was not hiden by the slip lock blade, it is on the opposite side. I really like this design, I just wish they had made both blades back lock's. HL