A box containing a large number of spring bars for your watch straps, sorted into all of the most popular sizes from 8mm to 25mm. We find this particularly handy when new watch straps don't come with spring bars, the ones already on the watch don't fit the strap holes, and for replacements when a spring bar fails or gets lost. (They can sometimes spring away quite a distance when removing them and be hard to find, pesky things!)

One handy tip for watches that have shallow lug notches and for NATO straps is to try a size higher than the lug width. For example, if your watch lug width is 22mm, see if you can use a 23mm spring bar instead. This usually works and provides a firmer pressure from the springs to help keep the spring bars more securely in place.