The Hydra® SM Personal Series Cigar Humidifier is designed to automatically regulate the humidity inside large desktop or mini cabinet humidors up to 8 cubic feet in size.  The internal computer senses changes in humidity within your humidor, turning a fan on to circulate more humidity and turning it off when the desired humidity is reached.  You may also add up to 3 optional external fans (sold separately) to extend the Hydra's humidification capabilities even further!  Product details include a large LED for easy viewing, humidity reports every 30 seconds, HygroSet® adjustable technology, refillable and replaceable foam filled water cartridge, one internal fan, two external fan ports, low water indicator, and instructions.  Measures: 6"L x 2"W x 3 3/8"H.