Technical Divers who use Aluminum or Stainless Steel Back-Plates have a need for Attachment of Accessory Items. Most Back-Plates have Holes on them specifically for this purpose. Book Screws are used to anchor the accessory in place to keep them secure and close at hand. Highland by XS Scuba's Stainless Steel Book Screws are Non-Rusting and allow the diver to Attach Accessories to their Back-Plate. Book Screws come as a complete set with both Male and Female Threaded Components and include Friction O-Rings. Book Screws are designed to pass through 3/8" (9.5 mm) Back-Plate Holes. Book Screws make a Great Save-a-Dive Kit item.