I have measuring and eletronic devices in my shoe rack, bought a Xiaomi's meter to check the temperature and hunidity. It's availabie on AliExpress or other global malls, but as they're imported and being sold, so you don't need to buy from there.

A meter, holder, double-sided tape, magnet, and manual is in the pacakge. You can use the tape put it on a wall and the magnet on a refrigerator. The display is E-ink(electrophoretic display) and it will not consume power unless displaying content is changed.

You have to pull and remove insulation film on the battery before use it first. I've pulled it out while the down side of the back plate is opened. It will need more strength to detach the upper part of the plate, you have to be careful. It uses one CR2032, 3 nominal voltage lithum battery.

I've checked the values after put it in the shoe rack. It seems the temperature and humidity is adequate as air-conditioning is working in the room.