Pneumatic Damper Actuator, Direct Linkage - Adj 1st Stage 3PSI Start 3PSI Ring 2nd Stage 9PSI Start 3PSI Ring, Constructed of: Die Cast Aluminum Housing Enclosing a Molded Neoprene Diaphragm, Steel Piston and Piston Shaft, Sintered Bronze Shaft-Guide Bushing and Steel Spring, Weight: 4-Lbs 11-oz, Dims: 5-1/4"H X 4-1/4"W X 7-1/2"D