1/8" FNPT M style plugs have a 1/4" basic flow size and a maximum pressure of 300 PSI. The industry standard M style couplers come with a Buna-N seal and air flow of 40 SCFM. M style plugs are made of case hardened steel and are plated to resist rust.
1/8" female national pipe thread
Maximum inlet pressure of 300 pounds per square inch