Dynalite Alpha Four Vintage Light Chaser Audio Light Equipment. All buttons appear working. A genuine vintage Light Chaser. Designed to be used with four channel light boxes. The DBO is a blackout switch. Chase 1~3 are programmed patterns. Flash is exactly that ant STL is like pause. The Rate is the speed of the lights and Gain is how sensitive each light is to sound to activate the lights. The more Gain the more sound activated it is and the less gain will lean on the program sequence.