This product has a variety of specifications, factory direct sales, 30, 35, 40, 50, one to a message that did not specify the default length of 50. Special specifications can be customized please contact the owner. Can also explain. This shop can sell any specifications of diamond grinding wheel cutter, diamond diamond pen, welcome to order, we use natural diamond system, reasonable structure, beautiful shape, inlaid solid, durable. Where to buy the store knife grinding wheel, there are quality problems in the use of that, three packs of products (guaranteed repair, replacement, return).