Check the listing for details. MTH 9 Volt Battery Super Capacitor Replacement PS1 & Early PS2 8.4 Volt - BCR 9V. Color: Black, Condition: New. Listed at 21.99 USD. Offered is a super capacitor component replacement made in a 9 volt battery case. This configuration allows you to simply plug it in and mount the battery replacement device in the same location as the factory 8.4 volt battery. It is widely known that capacitor replacements are a game changer when running older MTH locomotives. The device can be used in QSI / MTH Proto Sound 1 and Early PS2 5 Volt systems using the 8.4 ( 9 volt ) rechargeable battery. We are have been running MTH trains for 30 years and use these in our locomotives. Included is a adhesive backed Velcro set if you want to mount the device to the frame. Please contact us if you need assistance in identifying the type of battery replacement you need. We ship to the lower US 48 States only. Feel free to ask questions.