Description: 100% brand new and high quality Couplers made of Iron plated nickel and plugs made of case hardened steel plated to resist rust All the outside thread with sealant, better sealing Zinc plated steel coupler features high corrosion resistance and long life Air fitting kit for air tools, air compressor, air nailer, air blow , pressure washer, air hose Specification: Material: Iron plated nickel Color: Silver Size Chart: 20SP: Length: 5cm (for PU Hose external diameter: 8mm; Internal diamter: 5/5.5mm) 20PP: Length: 4cm (for PU Hose external diameter: 8mm; Internal diamter: 5/5.5mm) 30SP: Length: 5cm (for PU Hose external diameter: 10mm; Internal diamter: 6.5mm) 30PP: Length: 4cm (for PU Hose external diameter: 8mm; Internal diamter: 5/5.5mm) 40SP: Length: 5.5cm (for PU Hose external diameter: 12mm; Internal diamter: 8mm) 40PP: Length: 4.5cm (for PU Hose external diameter: 12mm; Internal diamter: 8mm) 20SH: 5.3x1.5cm (for internal diameter: 8-9mm) 20PH: 6x2.5cm (for internal diameter: 8-9mm) 30SH: 6.3X2.5cm (for internal diameter: 10-11mm) 30PH: 5.3X1.5cm (for internal diameter: 10-11mm) 40SH: 6.3X2.5cm (for internal diameter: 12-13mm) 40PH: 5.8X1.5cm (for internal diameter: 12-13mm) 20SM: 4.8X2.5cm (for external diameter: 13mm; male: 1/4) 20PM: 3.8X1.5cm (for external diameter: 13mm; male: 1/4) 20SF: 4.5x2.5cm (for internal diameter: 13mm; female: 1/4) 20PF: 3x1.8cm (for internal diameter: 13mm; female: 1/4) 40SM: 5x2.5cm (for external diameter: 20mm; male: 1/2) Package Includes: 1 piece Pneumatic Hose Coupler (4 Pack) Note: S for female, P for male, SH + PH and SP + PP these two models are specifically for trachea products. And with internal and external thread SM + PM and SF + PF is a special joint. If the air tightness requirements can be selected if the SP + PP, if the air tightness is not high, then you can choose SH + PH Pls allow an error of 1-3mm due to the difference of manual measurement.