US Divers Non Magnetic UDT regulator #237601
The regulator was used by US Navy UDT teams to disarm magnetic mines and so the regulator had to have very low magnetism. Since chromium has some magnetism, they did not use chrome plating on this regulator but they did need corrosion protection since it was used mostly in salt water. They chose to gold plate many of the parts including the nozzle (1012-12), the HP seat (1010-65), the spring block (1000-23), the LP seat holder (1010-04). and the LP seat retainer (1010-07). These gold plated parts are clearly marked as to distinguish them from the standard unplated brass parts. They all have a circular grove around the part to show it is non-magnetic and gold plated (see photo below). I also have a filter (1000-38) that looks like it is gold plated but it has no distinguishing marks.
Also, as many already know, all non-mag regulators had an unmachined hook-ah port on the regulator body and the entire regulator had a black oxide anti glare and corrosion resistant finish. I have seen many examples of these regulators and most have had many parts switched in them over the years. Many of them that you find today will have some chrome parts and will have many brass parts instead of the original gold plated ones. “Vintage Scuba supply” http://www.vintagescubasupply.com/nonmagnetic.html