Calibre No. U680 Maximum run time from full charge (Normal Use Condition) Approximately 6 months Movement Eco-Drive Signal Reception Global Radio-Controlled Strap Stainless Steel Water Resistant Water Resistant to 20 bar Case Stainless Steel Glass Sapphire Glass (Non Reflection Coating) Specification 24hrs, Date, Day & Month Display Eco-Drive (recharged by any light source, no need for regular battery replacement) Insufficient Charge Warning Function Overcharge Prevention Function Power Reserve Indicator Power Saving Function Global Radio-Controlled Summer Time ON / OFF .