WESTWARD Pneumatic Grease Gun: Cartridge/Suction, 1/4" Air Inlet Size, 40 psi to 120 psi Item 1ZTC5 Mfr. Model 1ZTC5 Product Description Air-operated Westward grease guns feature a pistol-grip handle for controlled, one-handed, trigger-activated operation. They require an air compressor with a nearby power source.