The E-OR is a passive 2HP 'selectable gate mixer,' which means that you can choose between two different gate sources, two trigger sources or BOTH using the three way switch per channel. Great for choosing between various rhythms, clocks, gates, etc. Perfect for manual fills and variation in your set! Matte black panel with white ink. The E-OR is diode protected, so combining two trigger or gate sources is what it is meant to do!