La Pump Two Stage Isolator 2in.The Isolator Cylinder has been designed with separate chambers for your penis and balls, with different levels of vacuum pressure, pulling your penis up and out, and pulling your testicles away from the body. This special cylinder is made with three chambers and two valves. In order for this 2 in. diameter cylinder to work to its fullest, you must be able to fill the penis chamber from side wall to side wall. This cylinder will only fit if your erect