Brass Compression Fittings, Pipe Fittings are widely used with Brass
Everbilt 1/2 in. x 3/8 in. Female OD Compression Brass Reducing Coupling Fitting 800899 - The Home Depot
Proline Series 3/4-in x 3/4-in Threaded Tee Fitting in the Brass Fittings department at Lowes.com
Amazon.com: SUNGATOR 1/4" Brass Fittings, Air Hose Fittings, 90 Degree Barstock Street Elbow, Hex Nipple Coupling Pipe Fitting Set, 1/4" x 1/4" Female Pipe,1/4" x 1/4" Male Pipe, 1/4" Male x 1/4"