LeLuv Ultima Penis Vacuum Pump, Soft Black Silicone Seal & 4 Sizes of Constriction Rings. The 3mm-thick clear, seamless, untapered cylinder is graduated in both inches and centimeters up the side. This LeLuv Pump Kit includea 18 inches of our premium, uncollapable, smooth silicone hose that matches the upgraded ergonomic grips, and our specially-designed Quick-Disconnect Fittings to offer trouble-free pumping sessions. You can even disconnect the hose from the cylinder and it will maintain vacuum!Silicone Sleeve: Made from soft and pliable Silicone that is delicate on the skin, this sleeve is perfectly designed for pumps sized 1.75" to 2.25" (4.5 cm to 5.8 cm) and is the perfect accessory for trapping vacuum pressure within the cylinder.Constriction Rings: We include a set of 4 rings in different sizes, choose the size that isn't too tight but offers good constriction. Place over the shaft of the penis using the handles. Once the ring is in place, continue using your pump as directed.