Once you've figure out how and where to best attaches the cleaner and the speed at which you pull him over window, then you get out a super cleaning result! The Kobold is purified in minutes without leaving streaks the windows. However, it works in my opinion only for straight windows, so square windows or dormer windows can be cleaned only with difficulty, or the edges and corners must all be nachgeputzt with hands, as the puck can not be recognized in corners due to its size. Or at least I have not it hinbekommen :) For just window-surfaces but it is a dream! The supplied detergent is very economical, odorless and clean excellent. The goblin has its price, but who do not like dressing up window will look good every euro invested. Compared to other "window suckers" the goblin is a clear advantage, because it renders and suck in just one movement done. The window you do not have time "vorwischen". I would recommend the puck VG100 in handling and earnings without restriction, a point deduction, there are only for the rather high price.