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. Add up to 3 optional external fans to extend the Hydra's humidification capabilities even further! Features include: Large LED for easy viewing, Reports humidity reading every 30 seconds, HygroSet® adjustable technology, Foam filled water cartridge, One internal fan, Two external fan ports, Audible and Visual low water indicator, Toggle switch to turn off/on audible alerts, ribbon cable. Dimensions: 6"L x 2"W x 3 3/8"H