It's a Waterproof Digital Thermometer TPM-10. The digital thermometer is a device which is used to measure the temperature of Vehicle, Indoor, Fish Tank, Fridge, Body. 

Features 

• Digital Thermometer Waterproof TPM-10
• Temperature Measurement Range: - 50℃ ~ 110℃
• Temperature Measurement Error: ±1℃
• Resolution: 0.1℃
• Refresh Rate: 1.5 ~ 2 seconds
• Operating Voltage: 2x AG13 button cells
• Operating current: 4 uA (Max)
• Probe Cable Length: 1 m
• probe length: 20 mm (1 meters waterproof probe)
• Operating Temperature: 0℃ ~ 50℃
• Storage temperature: - 10℃ ~ 60℃
• Dimension: 4.8 * 2.8 * 1.5 cm/ 1.89 * 1.1 * 0.59 inches 
• Application: Vehicle, Indoor, Fish Tank, Fridge Body Temperature Measurement.

(Note: Product Image are shown for illustrative purposes only and may different from the actual product)