J.W. Winco Inc. offers GN 741 and GN 742 aluminum fill/drain Pplugs with metric and BSPP parallel threads. These RoHS-compliant plugs are made of turned aluminum with a matte shot-blast finish. They are available in plain or with fill or drain symbol laser engraved.

The GN 741 types have an NBR synthetic rubber seal, while the GN 742 versions have a seal of Viton rubber. The seal is retained in a groove undercut in the mating face, which prevents it from dropping out and from extruding when the plug is tightened. For this reason, the seal can be of a softer material, which offers better sealing.

Metric pipe thread sizes from M14 x 1.5 to M42 x 2.0 are available.