PosTVac Ultimate Constriction Rings improve erection quality by restricting blood flow from the penis, making your erection harder and last longer. They will also increase sensation by forcing more blood into the head of the penis, where it is most sensitive. In addition, the tabbed wings simplify placement and removal. Ultimate Constriction Rings are compatible with PosTVac Pumps but are as effective as a stand-alone sexual performance enhancer.