These took only a few minutes to install, remove the original prop rod and use the included hardware to connect. The screws are a little long and I will eventually trim them down or get shorter length but its as simple as pre connecting the hardware and sliding it into place. Someone recommended putting the piston in the fridge to get it to fully collapse, this is a very good tip, as you want the windows closed fully when attaching the arms to the greenhouse. Also, when installing, slide the piston into position and install the keeper pin only, you can screw the piston into the arm after it is all installed. Hope this helps someone else, instructions were a bit confusing. Been a few weeks, still working great, closed first thing in the morning and in the evening, and open as the day warms upWorks as expected and takes the hassle out of everyday monitoring green house ventilation 100 % 24/7..There was an item left out of the box and the seller responded immediately and sent a new item that came promptly. While I just installed the item it appears to be functioning properly with no problems. You will have no complaints with customer satisfaction from this seller. I would order again without reservation.They were easy to install. They seem to work pretty well so far. However, I1 of the 8 that I ordered is defective and cannot be installed properly. The threads were missing on the bracket so the solar cell cannot be inserted. Clearly a factory defect.Got a greenhouse from Harbor freight, these work great for themBent within daysI was excited to use this opener for a self-venting cold frame in my greenhouse. Unfortunately it appears to be a hunk of junk, because it didn't open anything, the arms just buckled on the very first day. I'm returning it and trying a different brand. And the vent it was opening is far less than fifteen pounds.dworks great as intended