Fasteners designed with a groove under the head accommodate a rubber O-ring that compresses to form a complete seal, permitting full metal-to-metal contact.
The 18-8 stainless-steel fasteners are passivated per QQP-35 and withstand wet environments. Screws come in nominal sizes of #4 through 1/4-20. O-rings are available in a range of materials: silicone, flourosilicone, and Buna rubber. Custom finishes include black oxide and sand blasted. Special lengths or captive configurations can be tooled on request.