This is the reel that fits onto the toprail of the Splash SuperPool and Alpha pools. The solar covers attach to it and you can easily roll the cover up and store it on this reel while you use your pool. To cover your pool you simply unroll it off the reel. This size will fit a 17 x 28 up to a 21 x 41.5 pool. The reels will not fit onto the Omega pools.