I just installed this. I know they'll be a life saver maybe literally. What I wanted to pass on was that for those sit on top kayakers with accessory tracks, I installed them in the track by adding a washer that would fit inside the track. So the large washer was above the track and the small washer was inside the track and the bolt below. Then I used a screw driver to hold the bolt against the track wall and twist the unit until it tightened (a little tricky). So its installed an no new holes necessary in the kayak.