Features Durable&.Black Powder Coating Made of high quality of steel material for durability.Black Color powder coating for frame,looks nice and not rust. No Electric Power Needed&Automatic Solar energy sourced, no operating cost.Automatically open or close the greenhouse vents as temperature rises or drops. Overheating Protection This automatic window opener will help you maintaining the best growing temperature and prevent your greenhouse from overheating. Double Springs Two springs are more strong and better withstand Wind. Strong Force Lifts up to 15.4 Lbs(7kgs),suitable for most of greenhouse window and vent. Easy installation Comes with a fitting accessory pack and a detailed manual for easy installation. Working Condition&Maintenance Working Condtion: The start open temperature can be adjusted from 15℃-23℃ ( 59℉-73.4℉ ).(Adjust:Rotate the cylinder clockwise to lower the open temperature or anticlockwise to increase open temperature.)When the temperature reaches 33℃ ( 91.4℉ )or above, the window will be fully opened.The maximum open distance, from window sill to bottom rail, is about 45cm (18”).Maximum weight of the window is 7kg (15.4 lb). Storage and maintenance： All moving parts need to be lubricated after installation. Occasional lubricate is recommended.Please take off the cylinder from the opener when the window is not to be opened such as during winter time, to avoid any accident opening due to warm up climate.Lubricate and check the piston rod, make sure it can work smoothly if there is long time no work.The vent opener should be stored at a cool and dry place. Automatic Single Spring Silver Aluminum Vent Opener Automatic Single Spring Black Stainless Steel Vent Opener Automatic Double Spring Black Stainless Steel Vent Opener Automatic Double Spring Silver Aluminum Vent Opener 132 Lbs Heavy Duty Automatic Vent Opener Add to Cart Add to Cart Add to Cart Add to Cart Add to Cart Customer Reviews 4.3 out of 5 stars 49 3.8 out of 5 stars 45 4.0 out of 5 stars 28 4.1 out of 5 stars 282 3.5 out of 5 stars 22 Price $27.98$27.98 $29.39$29.39 $31.99$31.99 $30.99$30.99 $122.99$122.99 Color Silver Black Powder Coated Black Powder Coated Silver Green Powder Coated Material Aluminium Premium Steel Premium Steel Aluminium Premium Steel Springs One One Two Two Not Applicable Lift Capacity 15.4Lbs(7Kgs) 15.4Lbs(7Kgs) 15.4Lbs(7Kgs) 15.4Lbs(7Kgs) 132 Lbs ( 60kgs ) Maximum Window Opening 18"(45cm) 18"(45cm) 18"(45cm) 18"(45cm) 13''(33cm ) Power Solar Solar Solar Solar Solar Automatic ✓ ✓ ✓ ✓ ✓ Overheating Protection ✓ ✓ ✓ ✓ ✓ Open Temperature Adjustable ✓ ✓ ✓ ✓ ✓ Durable ✓ ✓ ✓ ✓ ✓