Stainless Steel Washers are normally used to distribute the load of a threaded fastener, such as a bolt or nut, in a corrosive environment. Large washers (Round washers and Square washers) are available in both metric and inch sizes. Locking washers are also available as spring washers, Nord-Lock wedge-locking washers, Bellville Washers, Cup Washers for countersunk screws, and both Internal and External Tooth Lock Washers.
Stainless Steel Washers (like any metal surface) should always be isolated from dissimilar metals, especially if likely to come in contact with an electrolytic environment such as salt water, to prevent Galvanic Corrosion. This might be in a situation where Stainless Steel Washers (and nuts and bolts) and used with Aluminium or Zinc based cladding or surfaces.