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.

Trough

This is the standard design for a built-up letter with a solid face. 

RIm Grooved

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.

rim faced

Rimless 

Rimless letters allow for the full face of the letter to be illuminated, and are the perfect option for small to medium sized letters.

Flat Faced