Lightweight, corrosion-resistant zinc head casting design incorporates uniform wall thickness and an integral patented muffler which keeps noise level below OSHA standards. 150 psi pre-lubricated air motor requires no external oilier. Pneumatically assisted mechanical air valve assures positive tripping. Springless sir motor construction prevents premature pump failure due to spring fatigue. Precision-machined, hardened steel slide valve for longer life. One piece pump outlet body withstands constant high lubricant pressures. Nitride steel plunger and bushings resist abrasion and prolong pump life. All pumps are 100% electronically tested to assure quality performance. Shovel-type foot valve adds mechanical priming to normal suction.