The screw wrench is a combination of a wrench and a screwdriver. So on the top of a wrench is on the front of the screwdriver. So when you hit the button the wrench on the tip spins.To loosen or tighten a bolt. The top of the rench can snap on and off so if there is a little bolt you can change the size of the wrench on the top of the screwdriver. Also you can still drill screws into wood. That is a screw wrench.