I already have this product for over 10 years. Once properly adjusted and taken over can no longer do passer.plus battery needed, without the nightmare of the son. more you can ask the carpet anywhere, eg on your bed, in the grass etc ... practical and not bulky you can take it anywhere. mine still works as well. I bought one for offrir.la person is really happy too. ps: with a USB 2 port it plugs everywhere and works on. I recommend it to all.