Item # 2989PPhttp://www.doheny.com/poolsupplies/Cover-Clips.html
Standard 1-Piece Cover Clips
Snap directly to pool top rail. Three per upright. Clips are approximately 5" in length. These easy-to-use, 1-piece clips snap directly to pool top rail to keep cover secure and prevent snaps and rips. The #1 reason for premature cover failure is an improperly secured cover. Strong winds can cause covers to rip by snapping the cover against the top and side rails of your pool. This happens when covers have too much material overhang. Three per upright.
Deluxe 2-Piece Cover Clips (shown in inset)
Double your protection against high winds!
Snap these clips around perimeter of pool forming a positive interlock between pool's top rails and pool cover. Use three two-piece clips per upright. Hi grade resin, designed to perform for years in harsh conditions. Clips are approximately 5" in length.
No water tubes ever again Review by Libby
For years I struggled with water tubes and constantly had to replace them. Water tubes are heavy and bulky. They get slimy and stinky after a winter in Ohio. They're difficult to clean. The reason I used water tubes in the past was because I get a lake winds and cross winds in the winters and the it used to just find a way to get under the cover and mushroom. I spotted these clips and although I had to buy several to put around my 28' pool, they work like a dream! I no longer have to struggle with water tubes (filling, lifting and cleaning) or worry about a mushrooming winter cover. Clip these things to the rail and you have a worry-free winter. I wish I had known about them 15 years ago.