There are humidification units that are designed for large cabinets/closets and others that are made to work in a standard-sized humidor, but the ones that are in-between were a problem. You could use a smaller unit, but it would have to work constantly. You could use a commercial unit, but the output is so high that you might over-humidify your stash. That situation is exactly what Cigar Oasis 3.0 Plus was created for.
Meant for table and cabinet humidors up to a 1000 cigar capacity, this is an ultra-precise unit that can be set to whatever humidity level you prefer. It features a large, backlit digital display for humidity and temperature, a whisper-quiet circulation fan that makes sure that every single stick in the humidor gets the moisture it needs, and a water reservoir large enough to last up to two months without refilling. If you're a perfectionist about the condition of your cigars, the Cigar Oasis 3.0 Plus can be accessed by your cellphone to monitor the humidity and temperature and you can even change your settings remotely (subscription required). It takes up very little real estate in your humidor but does a better job than most comparable larger units.
Dimensions: Length: 6" Width: 2" Height: 3.5"
Notable features -
Large backlit digital display for humidity and temperate
Improved ribbon power cable with micro USB connector
Improved foam reservoir core, treated to avoid mold'
Smart Humidor (wi-fi) technology allows for remote monitoring and control of settings (subscription required)
Humidity level can be customized
Quiet, efficient circulation fan blankets your whole humidor with moisture
Minimal maintenance, long-term humidification solution