1/2 NPT Female Solid Brass Three Piece Pipe Union Fitting Adapter – compressor-source

Uenede 2PCS Solid Brass Bulkhead Fitting 1/2”Female x 3/4”Male Double Threaded Bulkhead Water Tank Connector : Industrial & Scientific

Solid Brass 1/4 NPT Quick Connector Air Hose Fittings Air Compressor Coupler Plug - AliExpress

3/8 NPTF Female Union Tee Solid Brass Pipe Fitting T Joint Hose Conne – compressor-source

HOME-FLEX 1 in. CSST x 1 in. FIPT Brass Female Adapter 11-435-010 - The Home Depot

Brass Compression Fittings for Potable Drinking Water

1/4 x 3/8 Hose I.D. x Male NPTF Rigid Hose Barb Adapter Solid Brass – compressor-source

Five 1/4 NPT Female Solid Brass Pipe Unions Adapter Fitting WOG Solid – compressor-source

3/8 Double Female National Pipe Thread Galvanized Steel Union Fitting – compressor-source

LittleWell 1/2 in. Push-Fit x 1/2 in. Female Pipe Thread Brass Coupling (2-Pack) ACPF8FPT8X2 - The Home Depot