Specification: M8*90 (bolt diameter 6MM, screw length 90MM) Quantity: 5PCS Made of 304 stainless steel, it is durable and can be used outdoors. It has better rust resistance (Can be used in damp or water and will not rust). Hole size: Select a hammer 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. The expansion tube must penetrate the wall, and as long as the threaded part is long enough, the sleeve part is deeper and firmer. It should be noted that the expansion screws must be mounted on a relatively rigid substrate. The installed tensile strength in concrete is five times that of bricks. After correctly installing an M6/M8/M10/M12 expansion bolt in concrete, its tensile load is respectively 120 kg / 170 kg / 320 kg / 510 kg. Due to factors such as manual measurement and display differences, there may be slight differences between individual products and images, please excuse me.