ITEM NAME:2 Stainless Steel Butterfly Backplate Wing Nuts Bolts Screws Sets for Dive Description: Material: 316 Stainless Steel Bolt diameter: approx. 8 mm/0.31 inch Bolt length: approx. 3.5 cm/1.38 inch Maximum corrosion resistance and durability For tech diving backplate, donut wings, or other purposes Package Includes: 2 Pieces Screws 2 Pieces Butterfly Bolts 4 Pieces Washers Images & Text: Please allow slightly difference due to manual measurement..For tech diving backplate, donut wings, or other purposes. 2 Pieces Butterfly Bolts. 2 Pieces Screws. Material: 316 Stainless Steel. 4 Pieces Washers. Bolt length: approx.