[Smart Visual Doorbell] U9 smart visual doorbell with ERP mobile detection and snapshot functionality, requiring a WiFi connection for operation [Long Battery Life] Features a 3600mAh polymer battery, providing over 6 months of normal use and up to 1 year of standby time [Quick Charging] Fully charges in just 1.5 hours, ensuring minimal downtime [Cloud Storage] Includes 3 days of free permanent rolling storage with unlimited interactions [High-Quality Video] Equipped with a 640*480 resolution camera for clear visual communication Specifications: Material: ABS plastic Battery: 3600mAh polymer Power Input: 5V?1A Camera Resolution: 640*480 (300,000 pixels) Doorbell Dimensions: 136*72*35mm (L*W*H) Indoor Unit Dimensions: 55*42*25mm (L*W*H), 37mm height including USB Weight: Doorbell - 201g, Indoor Unit - 23.3g, Total - 224.3g Communication Type: Color visual smart intercom Storage: 3 days of rolling cloud storage Charging Time: 1.5 hours Standby Time: 1 year