I just bought another hygrometer by Reindeer. It is rectangular and will fit in big mouth jars. Near perfect cal. digital and no cal needed. If you live in a large city go to a cigar shop--the bigger the shop the better. Where I live cigars are a big deal. I tested the Reindeer and my Acurite in the cigar shops massive humidor. Wow--the cigar industry is beyond what I imagined. Look online too. About $23.00 on average--give or take--less Ebay but not worth the wait over a buck or two. I am using it right now for drying. CG