This is a Shock Absorber for Model 10/6 Titan Surge Actuators. Each titan Model 6 contains one Shock inside of it, this is a replacement for that shock. Each Model 10 contains (2) of these shocks. The performance of this shock is important to your Surge Coupler and replacement is fairly straight forward. This is Titans Part #1242600. If you are noticing while braking, that your trailer slams harder or even makes a loud bang, their is a very high likelihood that your shock is worn and needs to be replaced.