LTWFITTING 3/4 in. FIP x 1/2 in. FIP Brass Pipe Reducing Coupling Fitting (5-Pack) HF98R12805 - The Home Depot
Everbilt 1/4 in. OD Compression x 3/8 in. Flare Brass Adapter Fitting 800779 - The Home Depot
Forney 75535 Brass Fitting, Bushing, 1/4-Inch Female to 3/8-Inch Male NPT - Air Tool Fittings - Amazon.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"