Functional Overview: 1. LCD display 2. The opening size is 41mm in diameter (the measurement has a small error) 3. Overall diameter 45.2mm (the measurement has a small error) 4. Humidity display 5. Humidity measurement range 10 percent -99 percent 6. Humidity display resolution 1 percent 7. The humidity sampling cycle is 10 seconds (1 minute) 8. Humidity measurement accuracy andplusmn 5 percent 9. Rated voltage DC1.5v (1 AG13 button battery) 10. Temperature measurement range -50 to 70 11. Temperature measurement accuracy andplusmn 1 degree (under normal temperature) Battery installation: Flip to the back of this product Push open the battery cover in the direction indicated by the arrow Pi Put two LR44 button batteries into the battery slot