This is absolutely the best thing I have ever bought for my coop. Before I bought it my coop was often open and vulnerable to predators for far too long during the day, as I often leave for work an hour or two before it gets light in the winter, and sometimes get home well after dark.
It is easy-peasy to install - just four screws to fix it to the wall above the pop hole, and tie the string to your pop hole door - what could be simpler? The door opens and closes quite slowly, so there is no danger of ending up with half a chicken - they have plenty of time to get out of the way if they're in the doorway when it starts to come down!
The programming is simple to understand, and the opening options are extremely flexible:
Manual - push the button to open or close. You can set this as the default option, so that you completely control access in and out of the coop, or you can use it as an override feature (eg if you want to open the coop before the preset time, or close it before dusk, or if you need to close the door during the day to keep a chicken in or out for any reason).
Timer - just what it says - activates at a specific time.
Light levels - the best setting to use - opens and closes when the light reaches a certain level, so the door opens at dawn and closes at dusk. All you need to do is go out for two or three evenings in a row and watch your girls take themselves in to roost. Leave it an extra 5 or 10 minutes (to give a bit of leeway for the odd evening when someone is late going in for whatever reason), and then use the inbuilt sensor to check the light level. It gives you a reading in 'lux', which you then use to set the light level at which the door closes. For the morning setting either go out and check the light levels for a couple of mornings, or simply do a trial and error process by adding about 20 lux to the closing setting. (Eg: if your door closes at 150 lux then set it to open at 170 lux). It may take a few days to get it spot on, but after that you can just forget about it completely (apart from changing the batteries a couple of times a year!).
That flexibility is what I really like about this product - you can mix and match any type of opening and closing settings - I've currently got timer to open and light levels to close, but you can use any combination you want. It is also easy to install the opener quite a distance away from the door. I added a run to the coop, and had to change the position of the opener so that it was at right angles to the door, on the end of the run roof, with two mini pulleys and 5 metres of string running through them.
***** UPDATE**** This long length of string worked for a couple of years, but the angles involved obviously put tension on the string which strained the motor too much. It gave up the ghost a couple of months ago and I had to buy a new one. Totally my fault - when I felt the tension on the string it was the equivalent of pulling up something like a 3 kilo door every day (and my door is a thin bit of plywood - maybe 400g maximum) ! I have installed my new opener under the run roof, and even with the lower light levels I have been able to set it to open and close at dawn and dusk without a problem. I would strongly advise you to site the opener just above the pop door, with the minimum amount of string between door and opener.
One final comment about the company itself - their customer service is excellent. I had a minor problem with the timer a couple of months after I bought it. I phoned them up and they were extremely honest - they'd bought a cheaper batch of timer chips in an attempt to keep costs down, and half of them had turned out to be faulty. They sent me out a replacement opener, which I received within 4 days (and that's from the UK to France), and I replaced it and returned the faulty one to them. Needless to say, they've gone back to their original timer chip supplier, and my new opener works without a problem now.
I would not hesitate to recommend this opener to anyone who wants to be able to let their girls out without getting out of bed at a ridiculous time in the morning, or who wants to be certain they are shut in and safe from predators before they get home in the evening. An excellent buy!