The instructions come in English only and make no mention of a guarantee or how to get spare parts, but the machine really makes up for any such shortcomings. It's well made and solid, really something better than I expected in this price range. It's got plenty of power and yet not too much power that it tears through things which should make it stall.
I bought it for my son's birthday after reading Mr Simic's feedback below that he'd impressed the whole street with his knife sharpening machine. I fully believe that! My son has used it to grind his own knives and it handles the job easily.
It would be good to have some instructions how to change the sanding disc and so on.
Ultimately the proof of this machine is in it's function - Exactly what I bought it for and the reason it earns 5 stars.