Schedule 40 PVC Pipe Slip x Fipt Female Adapter (2 1/2" Dia. (1 Pack) 435-025 Slip x FIPT Female Adapter for Schedule 40 PVC Pipe . Used to connect two parts with two different end types Female adapter has a female (fipt) socket on one side and a slip socket on the opposing side. They are used to adapt a cemented or solvent welded connection to a male thread connection. Connect a 3/4 inch threaded pipe to a 3/4 inch smooth pipe, you would use a 3/4 inch Slip/Fipt Female Adapter.