The tri-stone bench stone uses three different sharpening elements in one package for the best results when sharpening.
These oil stones use a mineral oil type of lubrication.
Each tri-stone system has a different types of stone grits. These stones could be an Arkansas surgical stone which is a medium stone and fine stone for honing and the third stone would probably be a coarse stone for a more aggressive maintenance. It all depends on the style of tri-stone system.
Each stone is mounted on an easy to use molded plastic triangle, that is rotated depending on which stone you wish to use. (Each stone type is clearly labeled on the plastic mount, so there is no confusion there.)
To complete the functional design the tool is held upon a sturdy molded plastic base, that is weighted well enough to hold position on the work counter. Non skid rubber feet fasten the sharpener when in use.
These are normally used by chefs, culinary students/schools and of course a sharpening hobbyist.