This Female Threaded/Grooved Combination Air-to-Close Inline Diaphragm Valve has female threads on the inside and a groove on the outside of each end of the connection, providing a versatile and utilitarian solution for any system using grooved and/or threaded connections. This valve requires a 1/4 air hose fitting to operate (not included). Looking for a replacement diaphragm? Check out our 3 Inline Valve Diaphragms (1723-300) .