Ideal Security Inc. SKPHC Plastic Cap Washers for Nails or Screws Box of 500, 7/8 inch, White Plastic caps for use with nails or screws 500 per box Compatibility: nail sizes #11 & # 12, screw sizes #6 & #8, plastic cap 7/8" Diameter Use to install: roofing felt, rigid board insulation, sheeting, house wrap, radiant & vapour barriers