The CSL11 series is a reflector type LED. It has improved design and visibility and comes in four color variations with the name of the part number showing the color variation required. The reflector type suppresses light leakage towards neighboring areas. The case example shown is when only the letter “B” needs to be illuminated. When using a non-reflector type, light will leak through and adjacent letters will still show. Using the CSL11 reflector type will allow only the letter B to show while others are totally blacked out.