Lug width is the distance between the two lugs on your watch case, measured in millimeters. The lugs are the small protruding pieces on either side of the case that hold your strap in place. In this guide, we’ll break down everything you need to know about lug width and how to measure it accurately. Lug width (also called “lug size” or “strap width”) refers to the distance between the two lugs on a watch case where the strap or bracelet attaches. The lug width or lug size of a watch describes the space between the two lugs of a watch case. Between the lugs, the strap is fitted to the watch case with the help of spring bars. Lug width – which is almost always provided by brands, unlike lug-to-lug — tells you the size of the opening between two lugs on the same side of the case. This measurement tells you what size strap your watch requires, and usually is between 18mm and 22mm for men’s watches. Lug width is the internal measurement between the two lugs of a watch. This is the most important measurement when purchasing a new watch strap as it is this measurement that determines the size of the strap you would buy; if you have a watch with a 20mm lug width, you will need a 20mm watch strap. A watch lug width is an internal distance between the two horns of a lug, measured in millimeters. This measurement is important because it helps determine the strap size that will fit on the watch. Lug width is the internal distance between the two lugs on one side of the watch case — measured in millimeters. It’s the gap your strap end must fit into exactly.