This simplified design improves serviceability and reliability in the Graco Husky 307 pump. The air valves are able to use compressed air make it very efficient for lower operating costs. Lubricant air is not required. The Graco Husky 307 Pump- Acetal Body, Acetal Seat, PTFE Balls and Diaphragm has a rest button that is convenient for restarting under tough conditions.