4 pack, 1/4" fnpt m style coupler, use for connecting air tools to an air hose or any pneumatic system components, with corrosion resisted plated brass & buna-n seal, connection 1/4" fnpt & m style plug, couplers designed to accommodate multiple pneumatic systems & tools, plated & coated with corrosion resistant increases servicing life, sleeve guards help reduce the potential of accidental disconnects & protects the coupler sleeves, includes: 4 female m style couplers.