|Cadmium and dichromate plated thumb screws.|
These thumbscrews are plated first with cadmium and then treated with acidified dichromate salt solutions to convert the surface layer of cadmium metal into insoluble cadmium chromate, which doesn't corrode and produce toxic cadmium oxide dust.
Source: eBay seller seismoman
Contributor: Theodore Gray
Acquired: 28 February, 2009
Text Updated: 16 April, 2009