Essentially, Troughs are the opposite of a flat-faced letters. The face of the letter has a sunken effect and is open with a solid back. It's the letter of choice for those wishing to create a retro design with LED bulbs embedded into the face.
Rim-Faced, built-up letters are the standard manufacturing method for acrylic faced letters when illuminating with LED. This type of built-up letter has the most strength and endurance.
This is the standard design for a built-up letter with a solid face.
Similar in appearance to the rimless letter but to add strength a groove is routed for the return to sit in the face; adding extra strength.
Rimless letters allow for the full face of the letter to be illuminated, and are the perfect option for small to medium sized letters.