The Norton IM100 3-in-1 Tool and Knife Sharpening Systems are designed for small straight-edged tool sharpening. The compact self-contained three-stone systems are optimized for the general sharpening of woodworking tools, cutlery and small knives. The base unit acts as an oil reservoir and permits continuous submersion of the two unused stones keeping them cleaned and saturated. Simply rotate the handle to expose one of the three mounted stones. Stones measure: 6" x 2" x 1/2"