Do you mean a specific kind of valve? Because a vacuum pump has to have some kind of valve to maintain the vacuum (to keep the air you pumped out from being sucked back into the cylinder). Some penis pumps have the valve attached to the cylinder (so you can remove the hose if you feel like it), but for anal use I find it more practical to have the valve on the pump so I don't need to awkwardly reach around my body to release the air pressure. I would go for a cheap penis pump where y