This accessory pack is for the Logitech Squeezebox radio and contains a rechargeable battery pack and remote control - the current product description is not very clear! The pack is very expensive for what you actually get - Amazon themselves do not currently have it on offer, only third party sellers, and I found the best deal was direct from Logitech with their price including trackable delivery via UPS.
The battery pack seems to be essentially eight AA size Ni-Mh cells strapped together with some charge/discharge circuitry and a connector - at the price I had expected a special Li-ion battery like for camcorders etc. The pack makes the radio quite a bit heavier and is a bit fiddly to fit - the battery needs to be inserted with the cable upwards and to the same side as the connector inside the radio. With the cable folded back on itself, as per the illustration in the included booklet, the connector from the pack will then be the correct way up to be inserted into the radio - it will only fit one way but you need good eyes to see how! With the battery connected an icon appears on the radios status bar, next to the WiFi indicator, showing battery state -on the pack Logitech estimate 6 hours use with the battery but it depends on many factors.
The Remote Control is small and is powered by an included lithium CR2032 battery which is activated by removing an insulator from within the control. Getting to the battery is not obvious - but is easily done by following the illustration in the booklet. The control duplicates most of the radios function buttons - not the memory buttons - but some appear slightly different. The Alarm bell on the radio is a sleeping eyelid on the remote and the jog/shuttle wheel and Back button on the radio are replaced by up/down and left/right arrows on the remote. Button up/down = wheel clockwise/anticlockwise - left = back and right = enter.
I have been extremely pleased with my Squeezebox Radio and this accessory pack gives it much more flexibility - but at a cost! If you want the radio to be fully portable or easily controlled from your armchair then this set will do that - if you just use the radio in the kitchen or bedroom you can save your money. A useful product with one star knocked off at the price.