EXTRA LARGE SIZE: Our double-sided, flattening stone has an extra-large total flattening area. Making it 3X times bigger than any other stone on the market & large enough to completely flatten any whetstone. DOUBLE SIDE FLATTENING STONE: This innovative Flattening Stone is different from any other flattening stone in the market. It is a two-sided, dual grit, grid flattening system designed to produce excellent flat surfaces on sharpening stones. Built from high-quality silicon carbide the flattening stone particles help in cutting sharpening stones material precisely. This makes it perfect for flattening as it cuts quicker and wears slower making it making it extremely strong and . DESIGN: Specially designed -shaped grid pattern of the grooves quickly and efficiently removes only waste material while flattening any type of sharpening stones, whetstones, Oil Stones or Ceramic Stones. DUAL GRIT: The 120 grit(Dark Grey) side is used to flatten coarse water stones with 900 grit & lower, this side provides the necessary cutting action to effectively flatten the stone. However, when flattening finer , a coarse grit leaves a finish that you many find undesirable. So we have designed #320 grit(Light Grey) side for water stones with 1000 grit and higher.