A standard channel letter is a three-dimensional graphic sign element. Its channel is fabricated from sheet metal commonly aluminum because it will not corrode. This creates the rear of the channel and is the basis for the letter contour. The sides of the channel letter, called the returns, are then formed by flexing a 3 to 6-inch-wide (150 mm) strip of aluminum sheet around the aluminum back. A translucent plastic face usually of 3/16" thick sheet acrylic fiber or polycarbonate is cut to fit the open face of the letter can. A trim cap border is applied to its borders which creates a fastening surface to attach it to the letter can and provides the letter face a finished look. When illuminated at night, channel letters draw on the eye of passers-by.
Reverse lit station letter
The wall floods that the letter is mounted to and creates a space that is negative at night. Letters in this style are also called ring letters. It is generally the priciest type to make.