As there are various types of channel letters in the market, you must take professional advice from an expert. Front lit channel letters are the most common ones. But these are greatly customizable. Reverse channel letters or back lit channel letters give a halo effect around each letter. Thirdly, combination lit channel letters allow you to have a specific face color with a suitable halo effect. Contact Color Envy Graphics for the best (http://www.sdcarwraps.com/channel-letters-san-diego-ca.php) channel letters in San Diego.