Milton® (715) 1/4 in FNPT M-Style® KWIK-CHANGE® Coupler. Milton Industries is proud to be the creator and leader of the pneumatic industry standard M-Style® Coupler. This 1/4 in FNPT M-Style® brass Coupler has a 1/4 in basic flow size, offering a maximum of 300 psi. Comes with Buna-N seal and air flow of 40 scfm. Milton® M-Style® KWIK-CHANGE® Couplers are made of brass, while M-Style® KWIK-CHANGE® plugs are made of case hardened steel and are plated to resist rust.