Double shoulder design allowing you to quickly and easily insert and remove for repair or adjustment. Installation Design: To ensure perfect flexibility and strength, both ends of the spring bar is inserted with high quality, longer lasting springs that makes it easier to squeeze ends for installation. Standard Diameter: 2.0mm diameter fits most bands and watches. Compatibility: Designed to fit any watch that uses standard 18mm, 20mm, 22mm , 24mm, 26mm spring bars. The size you need is the same as the lug width of your watch band. Package: You will get 4PCS spring bars per package. The spring bars here can only be used for watch bands which have the lug width of the spring bars selected. Made of 316L stainless steel, safe material, waterproof tested, not easy to corrode, rust or water.