Tritium Exit Signs are self-luminous and are very low maintenance.  No batteries and no electrical connections are required for these fixtures making them making them a very "green" product and allow energy costs to stay low.  Tritium Signs come in either a 10 year or a 20 year life depending on what your specific needs require.  A Contractor Lighting Sales Representative is available to assist you at 877-664-5483 or at info@contractorlighting.com.