Ice Crystal 2 Ounce Gel Jar
Quality Importers Trading Company designs and imports quality cigar humidors and smoking accessories, including cutters, lighters, ashtrays, humidifiers, humidifier solution, and more. They don't have quality in their name for nothing. Check out all of their accessories and buy with confidence.
I am using one of these and one of the "bead" type jars in a fairly small humidor - probably 30 or so max capacity. This appears to provide the most stable level of humidity. It is very easy to use. Just keep fairly full with distilled water and the two jars combine to hold humidity just shy of 70%, even when humidity in the house is at or below 30%.