MSD Ultra 6AL Plus Ignition Box Red # MSD6523Ignition Box, Ultra 6AL Plus, Digital CD, with Rev Limiter, Red, 4 6 or 8 Cylinders, Universal, Each Ignition Box Output: Capacitive discharge Circuitry: Digital Rev Limiter: Yes Timing Retard: Three stage Data Acquisition: No CD Voltage Output to Coil: 520 540 V Current Draw: 0. 8 amps per 1,000 rpm Spark Output (millijoules): 135 150 mJ Minimum Operating Voltage: 7 V Maximum Operating Voltage: 28 V Length (in.): 5. 200 in. Width (in.): 3. 300 in.