A waste of money ...

The device comes with only 2 instructions pictograms on the side of the box (no brainer you say). No clear indication is shown in the device for the implementation of FOUR batteries (the alignment keys are (mis) engraved under the hood).
This equipment is less efficient than an old cloth fluffy, he just spread the dust. In addition it carries out a circular cleaning (in the axis of folds) which is strictly not recommended by the manufacturers of CD / DVD / BD.
Use a damp microfiber, you will get better results.