【Features】Can be screwed directly into pre-drilled holes in concrete, and easily installed with a standard screwdriver. Silver-plated for excellent rust resistance. 【Uses】Various installations such as pipe saddle fasteners, switch boxes, curtain rails, storage shelves, air conditioning equipment, lighting fixtures, and interior base materials. Screw diameter: M6 Diameter (mm): 6 Overall length (mm): 75 Pilot hole diameter (Φmm): 5.5 Set of 3 boxes (75 screws total) The outer box will not be included when shipped; only the screws will be sent.