The Celestron Universal Mains AC to DC Adapter with multi-plug offering worldwide use, it is an alternative power source to batteries which can soon run out. Running your telescope directly off of AC power is hassle-free and much more reliable than other methods, especially in cooler evening temperatures, when batteries can run down quickly. - Power your Celestron computerised telescope from any AC wall outlet - 2 amp AC Adapter - Suitable for indoor or outdoor outlets - AC adapter comes with US, UK, EU, and AU adapter plugs AC Adapter Output: 12VDC Current Output: 2.5 amps (2500 milliamps) Tip: Inside tip positive Inside Diameter: 2.1mm Outside Diameter: 5.5mm Jack Length: 10mm - 15mm Compatible Telescopes: LCM | NexStar SLT | NexStar SE | SkyProdigy | Advanced | Advanced VX | CPC GPS XLT | CPC Deluxe HD