We've personally tested out these pumps and give them our seal of approval. This is a very nice premium cock pump & cylinder. Our Male Enhancement Pump System brings engorgement and heightened sensitivity to your penis. It comes complete with an airtight cylinder, silicone tubing, a professional-grade brass pump pistol with a vacuum pressure gauge, and a quick release valve for your peace of mind. The cylinder is also detachable if you are seeking to hold the suction while you play. The Vacuum Penis Pump is compatible and interchangeable with other Performance pumping accessories. We're had feedback from a few people that said they also tried the pumps on their pussy and nipples and it worked well. We offer our Penis Pump Kits in the following cylinger sizes: Dimensions: 1.75" dia x 9" cylinder length 2" dia x 9" cylinder length 2.25" dia x 9" cylinder length 2.5" dia x 9" cylinder length 3" dia x 9" cylinder length Pump Handle's Will Be Silver