Philadelphia Mixers Stainless Steel Pneumatic Mixer. Model: PGA-8-3. This portable, variable speed, clamp on mixer is powered by a pneumatic motor and gear drive which provides maximum torque output, reduces heat build-up and allows for spark free operation.. Impeller diameter: 12-1/2 in. Speeds can be varied by means of the air control valve. Pneumatic motor: 2.0 hp, 1750 rpm. Gear drive ratio: 5:1. Final rpm: 350. Air inlet: (1) 3/8 in. push on air hose fittings. Shaft length: 3 ft. 1-1/4 in. Shaft diameter: 1-1/4 in. Overall dimensions: 1 ft. 4 in. L x 8-1/4 in. W x 4 ft. 5-1/2 in. H. (ACN35)