The SuperDroid Trekker requires 8 AA Batteries.  This transformer has a plug end that connects to the OOPic II Expansion Card or the OOPic-R Expansion Card.  The AC plug can be used to power the Trekker.  If the batteries being used for the Trekker are not rechargeable, they must be unplugged when the Transformer is being used. 

This transformer can also be used to powering the wireless camera receivers.  

You can use this as a low cost alternative to charging your battieres.  Ideally you should use a peak automatic charger for your NiMH and NiCad batteries/battery packs.  We recommend the AstroFlight charger, it is a very good charger and will ensure your batteries are properly charged and last for many many charges.  The higher the mA, the faster the battery will charge.  If you use too low of a voltage transformer, the battery won't fully charge.  If you use too high of a voltage transformer, the battery or transformer will be damaged.  The table below is a chart that can be used to safely and effectively select the right transformer to charge your batteries.