Pure Physical Penile Exerciser Extender Vacuum Pump Penis Enlargement Belt Penis Stretcher Cock Massager Cup Sex Toys For Men 18 Feature: Cup Size S: Inner Diameter 33mm Cup Size M: Inner Diameter 38cm Cup Size L: Inner Diameter 42mm Sleeve Size S: Diameter 60mm Sleeve Size M: Diameter 80cm Sleeve Size L: Diameter 101mm Package include: AS The picture you choose. The vacuum cup simulates the shape of glans and is comfortable to wear. It is made of ABS safety material, Automatic air shut-off, no air leakage, lift the valve to exhaust. The silicone cover is soft and elastic. The L Cup matches the large sleeve by default, M，S Cup matches small size sleeve by default. How to choose the cup: Use a string around the thickest part of the glans when erecting, and then measure the length of the string. The inner diameter of the large cup is 42mm (the circumference of the thickest part of the glans is more than 13cm) The inner diameter of medium cup is 38 mm (the circumference of the thickest part of glans is 11.5-13 cm) The inner diameter of small negative pressure cup is 33mm (below 11.5cm); Product secret delivery, please make an order, rapid delivery, any questions please contact customer service.