This thermometer has a display with a blue backlight. It allows measurements of temperature of the connected sensor.

Technical specifications:
Connector: Loop-through 4-pin Molex
Measuring range: 0 ° C to 90 ° C
Power: From 5V PSU rail

Extent of delivery:
1x Thermal Sensor G1 / 4 "with C / F display

L ° C means: No connection (check cable from sensor to display)
H ° C means: Reversed voltage / short (sensor-display cable connected the wrong way)
-xx ° C means: same as H ° C