MultifunctionalThis pool hose adapter is used for saltwater system of above ground swimming pool. If your pool inlet/outlet and pipe holder are 1.25" , but you want to install a 1.5" plunger valve, the adapter B will be the perfect solution. Easy installationThe small end of adapter B attach to 1.25" pool inlet/outlet or 1.25" end of the holder, then fastened with a clamp. The other end attach to the threaded end of plunger valve, simply screw it on. WaterproofThe rubber ring on adapter B tightly with other pool parts to form a sealed space to prevent water leak. ConvenientIf you want to replace the filter element or upgrade a stronger filter, the plunger valve will help you to control water flow. Safe & Efficient Adapter B & Plunger Valve will work closely with other pool accessories to keep your pool running safely and efficiently.