p.2 #2 · Duracel alkaline batteries - as bad as you can get
and my rant continues....
I have these hygrometers which I keep in my dry boxes along with dessicants to make sure my gear is stored in a low humidity environment.
This exact one: Keep your ish dry
They run on AA batteries - one to be precise. Obviously you don't take the battery out like you would with photographic gear etc as it needs to constantly monitor the conditions.
Duracel - you suck asterisk.