All circuits are contained on the timing plate. Theres no module or anything else to mount! Model HDE-3 has eight advance curves and an eight-stage rev-limiter adjustable from 6000 to 7500 RPM or off. All models have the Accu-Ray timing LED for precise timing and system check. They work with the factory VOES switch (HDE-3 offers dual-range operation). Compu-Fire OEM # 20600
Note
Fits Harley-Davidson Big Twin 70-99, Sportster XL 71-03