The Nest Protect has been redesigned from the inside out. It has an industrial-grade smoke sensor, tests itself automatically, and lasts up to a decade. It's also the first home alarm you can hush from your phone without any extra hardware required. And just like the original Nest Protect, it tells you what's wrong and can even alert your phone. Nest Protect has a friendly human voice that gives you an early warning. That way you can handle burning toast before it becomes a burning toaster. No one should be woken up by a low-battery chirp at 2am. When you turn off the lights, look for a quick green glow. That's our Nightly Promise. It means all your Nest Protects have tested themselves, the batteries are good, and there won't be any chirps. Sweet dreams. Heating systems can cause carbon monoxide leaks or spread smoke through your home in a fire. In an emergency, Nest Protect tells your Nest Thermostat to turn off the heat to keep the danger from spreading.Specifications Generation: 2nd Generation Power: Wired, 120v Speaker: 2 Watt Horn: 85dB SPL at 10 feet (3m) Light Ring: RGB color ring with 6 LEDs Requirements: Wi-Fi Connection, Internet Access, Nest AppSensors Split?Spectrum Sensor, 450nm and 880nm Wavelength 10 Year Electrochemical Carbon Monoxide Sensor Heat Sensor, ' 1.8'F (' 1'C) Humidity Sensor, ' 3%RH Occupancy Sensor, 120' Field of View to 20 Feet Ambient Light Sensor, 1-100k Lux Dynamic Range Omnidirectional microphone, 70dBA SNR Wireless: Wi-Fi 802.11b/g/n @ 2.4GHz, 802.15.4 @ 2.4GHz, Bluetooth Low Energy (BLE)Includes Nest Protect (Wired) Nest Backplate Nest Screws (4) Nest User's Guide Nest Welcome Guide Nest 5 Year Warranty.