Feature:1. Adopts sapphire crystal glass with a hardness rating of 9, second only to diamonds.2. High transparency, smooth edges, no scratches, safe and reliable to use.3. Easy to install and disassemble, suitable for watchmakers and watch repairers.4. The is smooth, high temperature resistant, scratch and wear resistant.5. Double domed watch glass, exquisite in workmanship, directly replace broken parts.Spec:Item Type: Watch GlassMaterial: Sapphire CrystalQuantity: 4pcsSpecifications Model (Lens Diameter): Approx. 28mm / 1.10in, 28.5mm / 1.12in, 29mm / 1.14in, 29.5mm / 1.16inError Range: Edge Thickness: Approx. 1-1.2mm/0.04-0.05inDiameter Error: ±0.2mm / 0.01in Package List:4 x Watch GlassNotice:1. Please allow 0‑1 inch error due to manual measurement. Thanks for your understanding.2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.