1/4" FNPT A style push type coupler are easy to use; simply push plug into coupler to engage, pull sleeve back to remove. A style couplers have a basic flow size of 1/4" and a maximum air flow of 34 SCFM.This set includes 5 x 775 Couplers, 5 x 778 Female Plugs, 10 x 777 Male Plugs.