Don't skimp on your air line. Our 25 foot hose has a 3/8" interior dimension allowing maximum flow to your air tools. Reinforced with synthetic yarn the EPDM (ethylene, propylene, diene) hose has a 1,000 psi burst rating and a standard use rating of 300 psi. Soft plastic sleeves slide over the 1/4" machined brass fittings to protect from accidental hits to your vehicle. I've included our Danish made Increased Air Flow Anti-Jam Couplers. You'll receive 1 coupler and 3 male inserts with standard 1/4" NPT fittings. The unique spring action sleeve provides a quick connection of the air hose and tools. Simply pull back on the outer ring (it'll click open into the receiving position), and insert the fitting. Say goodbye to struggling with ill fitting couplers. The larger diameter air passage allows more air flow improving the performance of your air tools and HVLP spray guns.