Alternately flashes two 1.7mm diameter, high-intensity, lens-end lamps (included) at a slow rate to simulate ditch lamps. With the addition of a DPST or DPDT switch, the DL-1 circuit can be bypassed so the lights stay on. Requires 2.4-3V DC input from batteries, TP-2 #800-2002 or TP-3 #800-2003 Track Power Adapters, sold separately.