From Slovakia, this is the stone we use for sharpening in the field. It is a high quality, extra-fine stone which gives a long-lasting edge when used well.
To be effective, it requires more pressure to be applied during honing then the other stones we supply. This means it can be more tricky for the beginner to get a good edge with this stone until they have got the feel for sharpening. We would recommend most people to begin with something like La Saurat, then progress to this stone as their experience increases.