Pipe Couplings (Aluminium Alloy) Union Adaptor/Unified Attachment End, 3/16" to 1", 3/16" to 1/2" , 5/8" to 1", 11/4" to 2" – for use with "O" Ring Gaskets (in American) (& 10050) or equivalent AGS3018 Tapped Bosses
Data Sheet by SAE ITC TSC Aerospace Standards (Formerly ADS Group Limited), 07/01/1975