Part No. 2173. Fits 7" Steel, 8" Steel, & 8" Resin frames. It is made out of steel. It measures 5" 5/8" wide, 3" 3/4" deep and 3/4" tall. This part has been discontinued. If you have a 2173, you can replace it with part 2177 along the top of your pool or you can buy part 2277 for use along the bottom of the pool.