Good effect, need good batteries, bad cap

Tried in Sweden holidays with the family - was very popular. One must also be aware that the part of course takes a lot of power. Batteries are too expensive because in the long run, so you should already using very powerful and high-quality batteries. Point deduction is available for the blue cap of the battery compartment - the locks do not clean and due to the spring pressure can already imagine that this will be the weak spot, where the device is broken. Here, the design engineer has been sleeping. I would try it next time with the "mouse".