Milton 211 5pc adaptor kit. Five piece M style coupler kit includes various couplers and plugs with a 1/4″ basic flow size. Milton M style Kwik Change couplers are made of brass, while the M style Kwik Change couplers are made of case hardened steel and are plated to resist rust. This collection of couplers, plugs will interchange with all manufacturers who comply with the dimensional requirements of military specification MIL-C-4109. Kit includes one 1/4″ FNPT coupler, three 1/4″ MNPT plugs and one 1/4″ FNPT plug. M style couplers and plugs offer up to 300 PSI and has an air flow of 40 SCFM.