This is an absolute must for anyone looking to store cigars even for a little while. It works wonderfully right of the bat without any calibrating necessary. It's very accurate and handily stores the high and lows, so you can see fluctuations.
It is also quite small with a magnet glued to the back and a metal plate with double sided tape. This allows you to freely place the meter by sticking the plate somewhere and still be able to remove the meter hassle free.
As said, this is an absolute must have.