1089DC-RU Russian Backlit Magnetic Bluetooth 3.0 Keyboard for Microsoft Surface Pro 7 6 2017 4 3 1. Bluetooth 3.0 standard interface 2. Effective operating distance: 10 meters 3. Modulation method: GFSK 4. Working voltage: 3.0-4.2V 5. Working current: less than 2.5mA 6. Standby current: less than 0.3mA 7. Sleep current: less than 40uA 8. Charging current: more than 200mA 9. Standby time: more than 100 days 10. Charging time: 2-3 hours 11. Lithium battery capacity: 550mAh 12. Sustainable working hours: more than 100 hours (light off) 13. Lithium battery life: 3 years 14. Button force: 80 +- 10g 15. Button life: 5 million clicks 16. Working temperature: -10 ~ 55 degrees Celsius 17. Dimensions: 295x220x5mm 18. Net weight: 346g