Nylon Screw In Plastic Spiral Expansion Anchors Self Drilling Insulation Fixing Plugs with Countersunk Head for Wood Panel Product Description The Nylon Screw-In Plastic Spiral Expansion Anchor with Countersunk Head is specifically designed for creating secure screw fixing points in wood panel materials including MDF, particle board, plywood, chipboard, and OSB where direct screwing can strip out over time. The nylon PA6 anchor is pre-installed into a pilot hole or screwed