Check the listing for details. PosTvac PTV Ultimate II Round Tension Bands. Condition: New. Listed at 24.95 USD. Pos-T-Vac Ultimate II Round Tension Bands are a popular choice in Tension Rings and are worth trying if you haven’t had success with other tension bands. The Pos-T-Vac Ultimate Round Rings are a high quality, medical grade method for managing ED (Erectile Dysfunction) and Premature Ejaculation. Pos-T-Vac is the leading innovator in managing Erectile Dysfunction and Premature Ejaculation. X- The PosTVac Ultimate Round Ring X (XS) inside diameter 7.6mm (.310 inches)1- The PosTVac Ultimate Round Ring 1 (SM) inside diameter 8.7mm (.355 inches)2- The PosTVac Ultimate Round Ring 2 (M) inside diameter 10.5mm (.430 inches)3- The PTV Ultimate Round Ring 1 (L) inside diameter 14mm (.55 inches)4- The PVT Ultimate Round Ring 4 (XL) inside diameter 16mm (.63 inches)