A standard feature in all Lincoln safes, the 12 dehumidifiers heat to a surface temperature of around 100-120 degrees F. The heat creates a natural convection that slowly circulates warm, dry air throughout an enclosure on a 24 hour basis. This increases the temperature of the air inside to several degrees above the ambient outside temperature. Expansion of the heated air forces the moist air outside through the small cracks on safe doors leaving the dry air inside. It is best utilized effectively when mounting horizontally at the bottom of the safe. The safe dehumidifier rod can be mounted against a wall as well. Lowering the humidity is a slow process. If you do not see the reduction of humidity after a couple of weeks then you may want to consider a longer unit or our PEET dehumidifier(M10).