Specification: M6 * 60 (bolt diameter 6MM, screw length 60MM) Quantity: 5PCS Made of 304 stainless steel, it is durable and can be used outdoors. It has better rust resistance. Hole Size: Select an impact drill bit of the same diameter as the expansion screw expansion tube and install it on the electric drill to drill the wall, the hole depth is the same as the bolt length. The expansion tube should penetrate the wall and as long as the threaded portion is long enough the sleeve portion is deeper and firmer. Note that expansion screws should be mounted on a relatively rigid substrate. The tensile strength installed in concrete is five times that of bricks, after properly installing M6 / M8 / M10 / M12 expansion bolt in concrete, its tensile load is 120kg / 170kg respectively / 320 kg / 510 kg. 100% customer satisfaction, if you are not satisfied with the product, you can always email us, provide you satisfactory service at the first time. Principle of use: Expansion is created by tightening a threaded bolt, causing the sleeve to expand into a barb against the walls. Note: Hole size: Select an impact drill bit of the same diameter as the expansion screw expansion tube and install it on the electric drill to drill the wall. The depth of the hole is the same as the length of the bolt. expansion bolts should be mounted on a relatively hard substrate and the place where the soft and easy to fall is unstable, such as the limestone floor space of the wall If the load has a large vibration, loosening may occur, so it is not recommended to install a ceiling fan.