Welded 1) 6gr,10gr,15gr,20gr,30gr............. 2)Filter driers weled with copper tube or flare nuts at both ends 1 Drier and filter apply to refrigerator, freezer that use R12, R22, R134a, 2 Absorbing extra water or moisture, strain feculence that might cause block problem,to aviod the system'icd jam'or'dirt jam' welded filter