Details: Digitrax 3004 - PM42 Quad Power Manager ? Get the benefits of short circuit management and auto reversing without adding more boosters! PM42 Quad Power Manager lets you use a single booster and divide its output into 4 power sub-districts for automatic reversing or to improve operation by preempting booster shutdown when a short circuit is detected by the PM42. If you want to improve operation but don't need the added power (or expense) of adding a booster, the PM42 is the right answer for you. Each PM42 can run 4 sub-districts off a single booster in any combination of regular sub-districts and auto reversing sub-districts. ? PM42 Features: Cost effective power management for 4 power sub-districts Short circuit management or auto-reversing for each sub-district Increases layout reliability by preempting booster shutdown, minimizes downtime by automatically restarting once a short is cleared. User selectable short circuit detection sensitivity to optimize operation with other layout equipment Auto-Reversing manages polarity mismatches on reversing track sections Auto-Reversing is automatic, no need for toggle switches or additional boosters PM42 connects to LocoNet to transmit information to your system No locomotive wiring modifications needed Note: External power supply is needed.