Stainless Steel, 3/8 MNPT x 3/8 Compression Fitting

LTWFITTING 3/8 in. O.D. Comp x 1/8 in. MIP Brass Compression Adapter Fitting (25-Pack) HF686225 - The Home Depot

Stainless Steel Compression Branch Tee MNPT

Everbilt 3/8 in. OD Compression x 3/8 in. MIP Brass Adapter Fitting 800669 - The Home Depot

6-DMC-6 Dixon Instrumentation Fitting - Stainless Steel Male Connector - 3/8 Tube OD x 3/8-18 Male NPT (Pack of 10) — HoseWarehouse

MCB-8-6N, NPT Male Bulkhead Connector, Dual Ferrule

MC-6-6N-SF, Flared Fittings, Single Ferrule

Stainless Steel 1/2 NPT Pipe Compression Fitting 3/8 & 1/2 Tube Con – Home Brew Stuff

Ham-Let 3/8 Tube OD x 1/4 MPT Stainless Steel Compression Tube Male Run Tee Comp x MNPT x Comp Ends 3002308 - 87955555 - Penn Tool Co., Inc

3/8 MNPT x 3/8 BSPP Female - Stainless Steel Adapter