SAE weld-on flange 1/2"~4" for 3000psi, AFS301T-,-- 1/2"~2" for 6000psi, AFS601T-,-- Carbon steel & Stainless steel 1.SAE weld-on flange2.1/2"~4" for 3000psi, AFS301T-,--3.1/2"~2" for 6000psi, AFS601T-,--4.Carbon steel & Stainless steel SAE weld-on flange