Four Independent Timers Apply 12 Volts. Controls A Nitrous/Retard/Lean Out System Of Up To 4 Stages. Extreme Precision w/Adjustments Made To The Thousandth/Second. 4 Ignition Retard Outputs Remove Ground From Retard Box. 1 Combination RPM Switch/ 4-Stage Timer Output. Remote Display Output For LED Dial-In Board RD1. Pro/Full Feature Allows Saving 2 Groups Of Settings. Illuminated Keypad And Display For Night Racing. Easy Push Button Programming; No Laptop Required.