Specification: M8*70 (bolt diameter 6MM, screw length 70MM) Quantity: 5PCS Made of 304 stainless steel, it is durable and can be used outdoors. It has better rust resistance (Can be used in humid environment or water and will not rust). Hole size: Select a hammer drill bit of the same diameter as the tube of expansion screw expansion 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 should 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 should be mounted on a relatively rigid substrate. The tensile strength installed in the concrete is five times that of bricks. After properly installing an M6 / M8 / M10 / M12 expansion bolt in concrete, its tensile load is 120 kg / 170 kg / 320 kg / 510 kg respectively.< /p>