You've seen these promoted as dehumidifiers.  We object to this as they are essentially just heaters.  They do work though.  By raising the temperature in your safe the relative humidity is lowered.  Some brands claim advantages from the air circulation and such.  This product does the job.  It warms the air without getting too hot.  Uses a lower watt density of about 5.5 Watts/foot.  Protects about 200 cubic feet.  Not recommended for use with desiccant.  Desiccant life is extended with a tight safe.  Heating rods work best with a leaky safe.Requires power.  Plug is supplied loose so that you can feed the cord through a small hole in the safe and then attach the wall plug.  Rated 10W. Made in the USA.