All of our mounts are hand made by us, using marine grade aluminum, not plastics that will break. Lock the back of the boat in place. There are two different mounts that fit on any 15 degree transom. Forget the ball and shaft method, these are built to last. Built to withstand the heavy torque wind and current can put on a boat. We came up with the design for a reason, to last longer than the boat can. We make each unit ourselves in our own shop. Not many companies can say they do that. Give us a call if you have any questions, concerns or if you just want to talk to real boaters & fishermen.