“SMD” is an abbreviation for “Surface-Mount Device”. It is a type of “LED” where the components are attached directly to the surface of a “printed circuit board”. In comparison to “COB”, high lumen (lm) output requires more room for the diodes. Comparison: Task Lamp TL5000 uses 120 x SMD for an output of 5000 lm, while Task Lamp X4 uses just 1 x COB for an output of 3800 lm. SMDs emit less heat, however, so they can be installed in plastic enclosures rather than aluminum or metal. This technology is often called second-generation LED.