I needed something to keep my Pool Cleaner from getting stuck on my main drain. After looking around I decided to try the Main Drain Clip-on from http://www.maindrainclipon.com I watched the installation videos and it looked easy. I should have seen the red flag because the video showed the installation on the pool deck from a couple of feet away, not at the bottom of the pool. The Clip-on must be installed into the holes of the main drain in order for them to stay in place. From the side of the pool I can see the holes, but it's impossible to get the Clip-on to stay in place. I decided to dive in and install it. That worked. The Clip-on lined up with the holes and stayed put. About 2 minutes later my Pool Cleaner came over and promptly parked itself on the drain and stayed there. Well, I was ready for that as the web site said that some cleaners might need 2 of the Clip-on's to work. I had ordered 2 just in case. So I dive down to install the other one. The second one is not so easy. I try to install it across the other on and finally get it to stay. The Pool Cleaner actually bounced off and I thought it was all good. Not so. A little while later I saw the Pool Cleaner stopped and I thought it was on the drain again, but it was off to the side, not on the drain. I pulled the cleaner up and found one of the Clip-on's stuck in it's craw. I quit trying for the day. There was still the one Clip-on attached and the Pool Cleaner still got stuck on it. A couple of days later I tried again and got the other Clip-on installed. The Pool Cleaner still got stuck, but it didn't pull the Clip-on's off. I tried several different arraignments of the Clip-on's, but none will keep my Pool Cleaner from getting stuck. I'm out $37, but as with all things YMMV.