Suitable for various surfaces
2 hexagonal expansion bolts (? 1/2in * 3in) in each set for concrete, and 2 stainless steel hexagonal screws (? 7/16in * 3in) for wood. Dimensions of hexagonal nuts: (1/2) inch. Distance between two holes: (1 1/2) inches. For concrete, please use (1/2) inch drill bit size.