The W7 Mini Diamond Whetstone can be used to sharpen hone or file any hard material. Unbreakable unbendable & convenient to carry. Handy Mini Whetstone 70 x 25 x 5 mm. thick. No messy oils needed sharpen dry or with water. Durable construction will provide years of consistent performance & reliable service. Set of 3 consists of: 1x Green Extra Fine. 1200 g. 1 x Red Fine. 600 g. 1 x Blue Coarse. 325 g.