The Custom Products Dovetail On/Off ASA use"s what CP calls "System Bleed" and "Virtual Resistance" due to the fact that it has virtually no resistance at all while turning it on or off. Simple to turn then snug it down with the last 1/4 turn to make sure that it stays on during play. System Bleed will bleed all the air from your tank lines allowing you to easily remove your tank after degas.