The Gizzmo was designed to absorb the expansion of winter freeze-up in the water skimmer. 1.5" Tapered head. Fits 99% of most skimmers. How does the Gizzmo Work? AC-MKW-GIZZMO$6.25 Above Ground Pools,Swimming pool accessories,Above Ground Pool Cleaners,Inground Pool Cleaners,Swimming Pool Chemicals,Chemical Feeders,Chorinators,Swimming Pool Covers,Swimming Pool Filters,Filter Cartridges,Swimming Pool Heaters,Swimming Pool Liners,Swimming Pool Pumps,Slides