Made of SUS304 stainless steel, so it will not rust even when used outdoors, and it has a diameter of 0.2 inches (5.5 mm), so it wont break even when using it hard. Drilling holes are required when used with hardwood materials. 1 box (100 pieces) *Includes 1 square bit (#2) Color: Brown; Screw size: Φ0.2 x 3.5 inches (5.5 x 90 mm); Optimal hole drill diameter: 0.18 inches (4.5 mm); Note: When tightening the screw with an electric screwdriver, please make sure that the electric screwdriver and screw head are vertical. Please note that when tightening at any other angle, the screw head may be torned or screwed.