Flexzilla 3/8 in. x 50 ft. Air Hose with 1/4 in. MNPT Fittings HFZ3850YW2 - The Home Depot
Air Hose for Pneumatic Tools 1/4 in. Male x 3/8 in. Female Brass Pipe Reducer Coupler Connector Fitting 150 PSI Maximum 1/4 in 18 NPT Home Garage or Professional Shop: Amazon.com: Industrial & Scientific
3/8 Inch Air Tube 1/8 1/4 3/8 1/2 Bsp Npt Thread Straight Joint Copper Plastic Fitting One Touch Hose Quick Pipe Connector - Pipe Fittings - AliExpress
Male Hose Barb Fitting 3/8 Inch ID Hose x 1/4 Inch MNPT | Legacy Manufacturing
Joywayus Hose Barb Reducer 1/4'' to 3/8'' Reduce ID Barb Fitting,Hex Union Brass Fitting Water/Fuel/Air - 2 Pack: Amazon.com: Industrial & Scientific