Description: Material: Silicone This is a set of 950 pieces new o-rings gaskets,the o-rings thickness 0.5mm, 0.6mm,0.7mm with different 19 sizes. 15 different sizes from 16 to 30 mm: 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 and 30mm. Rubber watch gasket set that is installed on the watch back case,can cover the gap between the watch band and movement Play a role in watch waterproof,suitable for watch repair and DIY watchmaker. Specification: Coil diameter: (15 size, each size has about 50 pieces) 16mm/17mm/18mm/19mm/20mm/21mm/22mm /23mm/24mm/25mm/26mm/27mm/28mm/29mm/30mm. Package Includes: 950 Pieces Watch Gasket Kit(2 Pack) Note: Since the size above is measured by hand, the size of the actual item you received could be slightly different from the size above. Meanwhile, please be reminded that due to lighting effects, monitor's brightness / contrast settings etc, there could be some slight differences in the color of the pictures and the actual item