R 1/2'' x Rp 3/8'' M/F Stainless steel Reducing Ring 16 Bar [2 Pieces] | Tameson.com
Reducing Nipple 1/2" x 3/8" Male NPT 304 Stainless Steel Pipe Fitting .5": Industrial Pipe Fittings: Amazon.com: Industrial & Scientific
1/2" BSP Male to 3/8" BSP Female 304 Stainless Steel Reducer Reducing Bush adapter Fitting - AliExpress
1/2 to 3/8 Reducer Faucet Adapter - Compression Brass Pipe Fitting, 3/8 Male to 1/2 Male Supply Line Adapter for RV Kitchen Plumbing, Water Hose Pipe Connector with Rubber Washer, (2 Pack) - Amazon.com