Automatic Vent Arm

Save time and energy and make greenhouse gardening even easier with an automatic vent arm. Engineered specifically to replace manual vent arm(s) in all HobbyGrower and Master-Gro? greenhouses, including the Apex? and Mini-Pro?. The vent arm features temperature-sensitive wax and spring tensions that have been optimized for the size and weight of HobbyGrower and MasterGro vents. Vents open when the temperature warms and close as the temperature cools.