... couplings 1.Size: 1/8''-6'' 2.Standard: BS ANSI DIN standard 3.Certificate: ISO 9001:2008 4.Surface: black, g ... CLASS CSurfaceHot Dipped Galvanized, Electro Galvanized, Natural finished, Chemical blackThreadsDIN, BS, NPT, Metric, BSPT, BSP, NPS (ISO7/1, DIN 2999, ... 1 Size of mild steel couplings: 1/4" 3/8" 1/2" 3/4" 1"1-1/4" 1-1/ ... 2" 2" 2-1/2" 3" 4" 5" 6" Useage of mild steel couplings: conncet ...