2″ x 6″ High Grade Diamond Hone by DMT:
325 grit is for re-doing or re-shaping damaged edges.
600 grit is for honing common tools.
1200 is for getting tools that are in very nearly perfect condition ready for stropping, see below.
(Our knives come perfectly sharp, stropping is the principle way to keep them mirror sharp. After many stroppings the edge can start to thicken a bit, 1200 grit will then bring the edge back to its original profile ready for re-stropping.)