Nylon Screw In Plastic Spiral Expansion Anchors Self Drilling Insulation Fixing Plugs Large Diameter for Heavy Load Product Description The Large Diameter Nylon Screw-In Plastic Spiral Expansion Anchor is engineered for heavy load applications in concrete, solid brick, stone, and hard masonry substrates where standard-diameter anchors provide insufficient holding capacity. With extra-large diameters of 14 mm, 16 mm, and 20 mm and a thickened nylon PA6 wall, this anchor