The welding flanges are machined from 6061-T6 Alum. Each dash number relates to the O.D. of the flange and the NPT thread size.
AN867-1 1-1/2” Dia 1/8” NPT
AN867-2 1-3/4 Dia ¼” NPT
AN867-3 1-7/8” Dia 3/8” NPT
AN867-4 2” Dia ½” NPT
AN867-6 2-1/4 Dia ¾” NPT