A supple, silky sleeve that helps cushion and protect the penis while ensuring an airtight seal during pumping sessions, the Precision Pump adds comfort and even more effectiveness to enhancement efforts.Slipping easily over most pump cylinder openings, the Sleeve features a snug interior and soft thickness for an extra hit of pleasure during pumping. Compatible with water based lubricants, silicone formulas should be avoided. Fits pumps of up to 3 inches (7.5cm) in diameter.