The New Pro Mini On/Off ASA has all of the features of the 2K5 ASA in a new Smaller and Lighter Package. This ASA use's what we call "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 durrig play. System Bleed will bleed all the air from your tank lines allowing you to easily remove your tank after degas. Fits any marker with a standard dove tail.