Key features: Xiaomi Smart Doorbell 3S Remote monitoring for peace of mind at home Head to toe with 180° diagonal ultra-wide view The new generation ultra-wide camera increases the vertical angle to 107° to ensure a clear, panoramic view of the entire area in front of the door. Ultra-clear vision with 2K resolution, clearer than 1080P 2K resolution images are of higher quality and capture more details than 1080P images, allowing you to see guests’ faces more clearly. Excellent night vision: See clearly in low or no light The new night vision sensitivity adjustment function can help prevent inaccurate night vision switches. The 6 built-in high power 940nm* infrared lights turn on automatically when it gets dark. You can see clearly even in low or no light. Professional IP65 water and dust resistant design IP65 water and dust protection allows stable performance in adverse weather conditions. Supports both lithium battery and wired power supply * Two power modes are supported. You can choose either a lithium battery or a wired power supply depending on your needs.