Spectrum Illumination Monster Series Linear Lights are used for both bright field and dark field illumination. Monster Series Linear Lights are built using Modular Board Technology (MBT). The reason that MBT is important is that when the boards are assembled in the housing, the LED spacing is the same on a single board as it is from board to board. The result of MBT is even illumination over the length of the light (connecting lights together create dead spots between lights because LED spacing is not observed).