What is a spanner? Spanners are used to fit, adjust, or tighten nuts and bolts. They come in many shapes and sizes to fit the specific nut or bolt they need to work on. How do you use it? You can use any type of spanners to loosen or tighten nuts and bolts but using the correct size will save you time and energy. Wrenches usually come in 6 sizes, defined by their hexagonal shape – 7mm, 8mm, 9mm, 10mm, 11mm, 12mm – and the length of their shafts – 10 inches long to 20 inches long.










