The MotoMaster Air Powered Single-Action Grease Gun is a single-action grease gun that offers the user complete control over the lubrication maintenance task. The air delivery pump head allows a measured amount of grease (approximately 1 g) to be dispensed with each pull of the trigger. This reduces the likelihood of over-filling that often damages seals and bearings. The handle and trigger are positioned to maintain an ergonomic working position which minimizes user fatigue and work related injuries. Refilling the grease gun is a breeze with 3 way loading. The priming process is also simplified due to the included Air Bleeder Valve. Simply refill the grease reservoir, engage the follower system, and engage the air bleed valve. Once complete, you are ready to dispense grease.