SkiVisions also makes their specialty stones for those other guy's edge tuning tools.  Remember, they are stones, don't drop them, they can break.

The following videos relate to these stones related to quality, maintenance, and using the tuning stick:

Related to why the SkiVisons stones are better than diamond stones:

http://www.youtube.com/watch?v=z4ZswN10nUI

Related to maintenance of the stones:

http://www.youtube.com/watch?v=i1DikQ0kWNk

Related to using the Tuning Stick

http://www.youtube.com/watch?v=Jbv8pE5eA98