1. Active the hygrometer

Tear off the film on the back cover of the battery.

2. Create a 75% humidity package, then season the hygrometer.

a. Take a bottle cap or another small container with salt.

b. Dampen the salt with water, but not so much. A damp pile of salt in the bottle cap is what you need.

c. Place the hygrometer and the container with the damp salt into a ziplock bag.

d. Leave the hygrometer and salt container in the sealed bag for approximately 8 hours or longer.

The salt and water mixture inside the sealed bag creates a humidity level of approximately 75%. Check the hygrometer reading through the bag, and if it differs from 75%, adjust the hygrometer to display 75% for accurate measurements.

3. Calibrate the hygrometer

a. Long press the toggle of °C/°F located in the center position.

b. Once the temperature value on the display begins to flash, calibrate the hygrometer by pressing the +% and -% buttons on the back and adjusting the humidity value to 75%.