The magic bar is an accessory needed to re-charge apple's magic trackpad and wireless keyboard without having the trouble to have always new batteries or the electric recharger with us; it recharges by a normal micro USB cable, full charge takes about 6 hours: this ensures you to have your apple wireless keyboard always 100% charge! The description of the accessory is quite simple: in the box, there is a small single cylinder that is the battery; this package includes just one battery, for one accessory. So, if you have both keyboard and trackpad, there is the possibility to order an additional battery. How to set it up? - open the battery slot of the keyboard or trackpad, put the round little cover you took away, in a safe place. it is no longer needed unless you switch to alkaline batteries again. - extract the 2 AA batteries from apple's keyboard or trackpad, then insert the brand-new magicbar single cylinder into the battery slot; push it till it fits perfectly on the contacts. - turn the coming out plastic cylinder till it gets tightly foxed. No coin is needed to re-open the box, as the cylinder stays one centimeter out. Together with battery in the box we find the alluminium base station, it is shaped like 2 long cylinders put together. But one cylinder is open, with a hole on the left, needed to insert the keyboard or trackpad in it: just slide the keyboard or magic trackpad till it perfectly fits with the base, there is no possibility to insert it the wrong way, it has just one direction; the micro USB cable, included into the box, must be inserted in its place, on the base station. Mistakes cannot be made! It is an inductive recharger, so, there is no need to push too much. the keyboard must just fit perfectly inside the base station. Advantages 1. you have a brand-new battery wich can be recharged via USB 2. the base station can be carried into a bag without any problem, it's very comfortable 3. this battery lasts 10 days, then it needs 6 hours to entirely charge; mine is up and running since a week and i am still with 94% of power 4. it has 500 cycles of full charge 5. forget batteries disadvantages 1. place the charger in a flat surface while recharging, so that the keyboard or trackpad cannot slip away. It's not convenient to insert a USB plug near the bed and putting the keyboard/trackpad to recharge over the pillow. A soft surface may move the accessory and prevent it from charging 2. there is no audio feedback when the magic bar finishes recharge. But we can check the battery status during keyboard use (not while attached on charger), at least on the mac osx bluetooth menu, the status is indicated with the exact battery level. 3. the accessory with included battery costs almost 39 euro, to have an additional battery for a second accessory you must spend another 33 euro 4. you can just recharge a device at a time. If you have both keyboard and trackpad without any energy, you must wait for one to recharge and then insert the other. This accessory can be found on amazon or on mobee technology's web site, customer care seems to be very responsive to needs and to answer questions.