Rebuilt Old R12 Vacuum Pump (1/4 SAE Male) to 1234yf Left Hand Male Thread. Internal thread 1/4 SAE adapter X 1234yf left-hand thread. The connector also has a 1234yf Lh female x 1/4 sae male adapter to change the r12 hose from 1/4 sae female to 1234yf female for bolting to a converted vacuum pump.