Lee Valley 1000g Carvers Multiform Slip Stone

These are Japanese water stones made in the European style.

One edge is curved and decreases from 1/2" to 1/8" over its length while the other side is tapered at an angle of about 30° for working the inside of parting tools.

This design allows you to sharpen a wide variety of tools from small to large gouges and all flat or V-shaped tools.