Brass return ring nuts used for assembling indicators HGFT, HGFT-EX, GN 743, GN 743.1, GN 743.2, GN 743.3, GN 743.4, GN 743.5, GN 743.6, GN 7403, HGFT-PR, HGFT-HT- PR, GN 744, HFTX, HFTX-EX, HFTX-PR, HFTR-PR, HCFE, HCFE-C, HCFE-EX on thin-walled tanks.