Types depend on use of a hub: Type A(flat type),Type B(single hub),Type C(dual hub). Different teeth numbers are available for every pitch. Materials :steel C45 and stainless steel AISI 304 and Q235,Q345 are available. Surface treatments :such as hardened teeth(45-55 HRC) /Zinc plated/Black oxide can be also carried out for a better wear resistance of the product.