Glass material: Dual curve sapphire. Coating: Anti-reflective coating on the inside. Case size: Width 39mm x Thickness 10.4mm. Carrying accuracy: ± 10 seconds per year (when worn on the wrist at temperatures between 5°C and 35°C). Battery life: about 3 years. Waterproof: Enhanced waterproof for daily life (10 bar). All our items are 100% authentic. Depending on the products, the proper transformer and adaptor are required to use them in your local country, where the voltage is higher than 100V such as 200V-240V. We are not responsible for the damage of this device if you use it without...