DH127 Series This is clearly stated in the manual for the item, their website, and we show their policy in the photos. PX112-2 Power Xtender - 2 pin. Use with Digitrax Series 6 and the new Series 7 decoders with 2-pin PX socket (or PX solder pad connections).
Adds a lot to locomotives that have trouble picking up power. This keeps my shorter GP9's running over tricky turnouts and also helps maintain very consistent headlights across my layout.