Big Green Egg Bluetooth Dome Thermometer with App. 

The Big Green Egg Bluetooth Temperature Gauge easily attaches to the dome of the EGG and enables cooks to remotely monitor cooking temperature right from their phone! The gauge’s free app connects via Bluetooth and allows users to create high and low temperature alerts, set a timer, and toggle between C and F temperature display.
Item #127358
Features:
• Bluetooth technology with mobile app support
• Backlit LCD Display
• Temperature range: 32° F to 842° F
• Rechargeable battery with USB port
• Simple installation in seconds
• Includes Big Green Egg logo protective cover
• Rechargeable, high-temperature lithium battery reaches full charge in one hour; 24 in/60cm USB charging cable included
• Fits all EGG sizes