Proper wine storage

I've read many articles about how to preserve good wine taste and now I know that temperature and humidity of the cellar are key features for storing wine. Considering these two musts I'm trying to choose a present for my grandpa, he collecting his wines for quite long and his cellar in the cottage makes me wonder. He's quite accurate about conditions in which he places his precious bottles. I need someone's advice at hygrometers I was looking at https://www.bestadvisor.com/hygrometers which one is the best for measuring both temperature and humidity? What other options for good present?
THNX in advance