1/2" UNF Male to 3/8"x24 UNF Female Reducer Oil Pressure Gauge Adapter Sump Plug

Thread : 1/2"x20 UNF Male Thread to 3/8"x24 UNF Female Thread. Female Thread : 3/8"x24 UNF ( 24 TPI ). Male Thread : 1/2"x20 UNF ( 20 TPI ). BRASS SUMP PLUG OIL TEMPRATURE SENSOR GAUGE ADAPTER x 1 piece.

eBay