This is XH-W1209 12V Digital Temperature Controller Module W/ Display and NTC Waterproof Temperature Sensor.
W1209 Mini thermostat Temperature controller is low-cost 12V Temperature controller with 7-segment display and 3 switch keypad for setting temperature and other parameters. The module features an NTC thermistor temperature sensing and has an accuracy of 0.1 C.
The XH-W1209 12V Digital Temperature Controller Module W/ Display and NTC Waterproof Temperature Sensor is an incredibly low cost yet highly functional thermostat controller. With this module, you can intelligently control power to most types of electrical device based on the temperature sensed by the included high accuracy NTC temperature sensor.
Although this module has an embedded micro-controller no programming knowledge is required. 3 tactile switches allow for configuring various parameters including on & off trigger temperatures. The on-board relay can switch up to a maximum of 240V AC at 5A or 14V DC at 10A.
The current temperature is displayed in degrees Centigrade via its 3 digit seven segment display and the current relay state by an on-board LED.