... Rack and pinion vent system is a system operated by transmission mechanism to ... open or close roof or side vent for greenhouse, it includes continuous vent, alternate vent, swing vent. Rack and ... Description:Specialized for greenhouse vent open and closeBig torque capabilityWide application usageStable performanceAccurate ... .6 rpm FLC-Gear Motor, Rated Voltage: 220v/380v, Rated Power: 0.55KW,0.75KW, ...