Hose connection end outside measurement is approximately 1 1/2 inches. Poolside connection end inside measurement is approximately 3 1/4 inches. fits Intex pool 28000E,28335EH,28337EH.28341WA.28345WA.28365EH.28375EH,28395EH Fits Intex Products: Wall Mount Surface Skimmer Dexlue Maintenance Kit The adapter connects the side of the pool to the skimmer hose, allowing water to flow from the skimmer kit into the filter Hose connection end outside measurement is approximately 1 1/2 inches. Poolside connection end inside measurement is approximately 3 1/4 inches. fits Intex pool 28000E,28335EH,28337EH.28341WA.28345WA.28365EH.28375EH,28395EH Fits Intex Products: Wall Mount Surface Skimmer Dexlue Maintenance Kit The adapter connects the side of the pool to the skimmer hose, allowing water to flow from the skimmer kit into the filter