AM-K series stones are made of aluminum oxide and have an average hardness

Tsushima is natural stone with estimated grit approximately 5000 JIS

Dota Creek stones may have a color pattern

Laser Goniometer is a tool of measurement of the sharpening angle of knives and scissors

non-toxic odor-free liquid

digital angle gauge AM-K series stones are madeIt's very important to keep a sharpening angle consistent on a guided knife sharpener. The angle should not change when replacing one sharpening stones to another. In order to control the sharpening angle, one measures the angle between the knife plane and the sharpening stone. There are many similar digital angle gauges on the market. This model is very light, which is a huge advantage when using with conjunction with a knife sharpener.