I have a Harbor Freight (HF) 10 X 12 green house that I will be setting up this spring. Harbor Freight stopped selling window opener kits for their green houses several years ago. I was quite pleased to find this window opener kit. I have gone all through this kit to understand how I will be installing it. The edges of the two arms or frames have a semi-rough touch to them, not enough to cause a cut, but still enough to warrant using some sandpaper on first before I install them. The process of getting the rod of the cylinder to thread into place requires precise alignment between the rod and the frame. (Please refer to the two pictures.) The maximum window opening is 18.5 inches and the rod is fully extended at 86 degrees Fahrenheit. Apparently, the window is fully closed around 50 degrees Fahrenheit. I will observe the opening and closing action of this window opener on a warm table, before I install it into the ceiling vent windows. I want to make any needed adjustments for the length of the travel before I install this into a roof vent window.I consider this kit to be a five-star product. The manufacturer provided sufficient hardware for installing these window openers into either metal framed windows or wood framed windows. All of the pieces line up and the opening action is smooth. The entire assembly weighs 12.5 ounces, so it will be easy to hold up overhead and install.