Spring bars are used to connect your watch band to your watch or connect a watch buckle or clasp to your watch band. The ends of the pins are double flanged and have a spring at the end of the bar that allows for easy removal and installation. Our spring bar pins are made in stainless steel. Large watches use 1.78 mm thickness. We offer spring bars in many sizes and thickness. Sizes available 10mm up to 24mm. To find out which size you need, measure the length of your old spring bar or if you are replacing a pin on a leather band, the inside of the band usualyl has the size imprinted on it or you can measure the distance between the watch case lug to lug (the area between where watchband goes). Most watch pins are measured in millimeter sizes. Use a ruler or a metric (mm) units to measures the pin or the distance between the case or lugs of the watch. Please select the correct size when ordering. Comes with installation instructions.