After driving the expansion screw into the hole on the ground or wall, tighten the nut on the expansion bolt with a wrench, and the bolt goes out. But the outer sleeve does not move, so the big head under the bolt expands the sleeve to fill the entire hole. Widely used in fences, anti-theft doors and windows, rain sheds, engineering, etc. Features - Color: Silver. - Material: Stainless steel. - Size: 8.60 x 1.80 x 1.80cm/ 3.38 x 0.71 x 0.71 inch. - Expansion screw bolts can be used in concrete and masonry. - Widely used in fence, burglarproof doors and window, canopy, air conditioning rach fixation, home decoration, engineering, etc. - Easy to install, drill a hole in the wall, clean the sand and soil in the hole, insert the expansion screw into the hole. - And use a wrench to tighten the nut of the expansion bolt out of the wall hole.