The GY-906 MLX90614ESF is a high precision infrared non-contact thermometer module with I2C interface and 5V or 3.3V operation. It is based on the MLX90614ESF sensor, which is a factory-calibrated infrared thermometer with a temperature measurement range of -70°C to +380°C and an accuracy of 0.5°C around room temperature. The GY-906 module also has a PWM output and an interrupt output, which can use to trigger other devices when the temperature reaches a certain threshold.