This hose fitting is included in the Hayward above ground skimmer packages. This is designed to thread into the wall fitting using the 1-1/2" male threads on the front. The opposite side is designed to fit a 1-1/2" inside diameter pool filter hose..(1-1/2" male threads actually measure about 1-7/8" diameter")
Dimensions and Specifications Thread diameter :1-7/8" (1-1/2" MPT) Length:3-3/8" Smooth end diameter:1-1/2" "SP-1091-Z-4" is molded on the side