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
Aignep USA - Pipe Reducer: 3/8 x 1/2″ Fitting, 316L Stainless Steel - 28735504 - MSC Industrial Supply