This Acculock MDX gas diffuser is made of brass. It features cooling tail, optimized wire-feeding, quick replacement, tapered connection. Plus, it is compatible with MDX-250, MDX-250 EZ-Select, 1770035, 1770036, 1770037, 1770038, 1770047, Miller brand and is for use with Miller MDX-250 MIG guns. It can be used for flux-cored welding (FCAW), MIG welding.