Alternate vent system includes Vent gear motor, drive shaft, rail vent rack and pinion, shaft supporter, wheel supporter, handspike,supporting wheel,rack and pinion connectors etc. It is ... to alternate vent system.NameModelSpecificationAlternate Vent PinionCLJC-1---Alternate Vent RackCLJC-1050L=1050 mmALternate Vent RackCLJC-1200L=1200 mm Rail Vent Rack and Pinion