if worry, buy another one and put inside ur dry cabinet, which I did.
Btw it hygrometer (instrument used for measuring the moisture content in the environmental air, or humidity)
Hydrometer is an instrument used to measure the specific gravity (or relative density) of liquids.
Video is often easier to follow... Just note that the Akarui's analogue hygrometer has a needle inside that can be pushed left or right to calibrate, instead of having a screw. It is as simple as that.