Midland Metal 700286 Pipe Connector, 1/2 in JIC x 3/8 in Male BSPP, Steel

Adapter, Connection Size 1: 1/2-in, Connection Type 1: JIC, Connection Size 2: 3/8-in, Connection Type 2: Male BSPP, Steel, 3/4-16 x 3/8-19 Thread