I've read some good things about these. It is said they use no Propylene Glycol and work with just distilled water and only need to be refilled every four months. They seem a little pricey but if they work as they claim to it would be worth it. Can anybody tell me more about these? Thanks!

I use them in two of my humidors, and love 'em. You will have to fill them more often, especially if you open your humi every day like I do. Make sure you buy one big enough for the humi. They make three sizes, I believe. These won't drip out on your cigars like some of the other brands if you fill them a bit too much.

I can also personally vouch for them. They are worth every sent. AND if you consider that they do not use glycol, they really aren't any more expensive than a regular humidifier. I can also tell you that they have doors on the sides that are removable, so you can get more or less humidification by removing or replacing doors.

Thanks so much for the input. Can anyone tell me what the lifespan of one of these is? 1 year? Two years? Is over-humidification ever a problem?

You might want to try the 65% beads from heartfelt. They work similarly, but are cheaper.

http://www.heartfeltindustries.com/Beads.htm

Never had a problem with too much humidity. I have been using mine for over 5 years now.

I use them in all my humidors and love them. Best of all is no chemicals just distilled water.