This fits your .

1/2" Male Threads x 3/8" Female ( M/F) Adapter Means 1/2" Outer Male pipe Threads and 3/8" Inner Female pipe threads This is a Brass Connector having 1/2" Male pipe threads in it to be use with 1/2" Female fitting and having 3/8 inch Female threads suitable to be connected for your 3/8 inch Male Fittings

Brass Fittings - 1/2" x 3/8" M/F Adapter - B07256KZRJ