Dr. Joel Kaplan's Pump Erection Enhancer is a silicone penis constriction ring that is designed to use with vacuum therapy pumps but can also be used on its own. The two-handled design makes it easy to slide the ring onto erect penis over the pump cylinder. This ring will help maintain a harder erection for a longer period of time by prevented reverse blood flow. *Not to be used with silicone lubricant.