These solid aluminum nails can be hammered into pre-drilled holes to fasten tackless strip or metal moldings down onto concrete subfloors, or onto tile or stone when necessary. The semi-square body compresses and holds against the walls of a pre-drilled1/8 hole. For carbide or masonry drill bits used to drill the1/8 holes for these fasteners, see our No. 2231/8 Solid Carbide Drill with No. 2251/8 Hexagon Adaptor. Fastener dimensions:1/8 dia. x7/8 long. Hole size:1/8 x 1.