DescriptionModel Number : Rear Derailleur Pulley SetTotal Capacity : 12T 14T 16TGears : 12 SpeedMaterial : POMType : Rear DerailleurOrigin : Mainland ChinaComponents : DerailleursFovno Rear Derailleur Pulley SetFovno is a high end brand of Deckas. Nice quality and design. High durable and stiffness. You will like it.Name: Fovno Pulley Wheel, narrow wide toothMaterial: POM high strength resin, steel bearingTooth: 12T/14/16TWeight: 12T 10g, 14T 12g, 16T 14gThickness: 8mmInner diameter: 5mmColor: black wheel with black coverFit for: 9 10 11 12 speed, for Shimano and Sram Derailleur(most)Package content: 1* pulley wheel, 2* side coverTooth OD(mm) Weight(g) Fit for12T 51mm 10g Most middle and long arm14T 59mm 12g Some long arm16T 66mm 14g Very less long armPolyoxymethylene (POM), also known as acetal, polyacetal, high stiffness, low friction, and excellent dimensional stability.POM is characterized by its high strength, hardness and rigidity to 40 C.Typical applications for POM include high-performance engineering components such as small gear wheels, eyeglass frames, ball bearings, ski bindings, fasteners, guns, knife handles, and lock systems. The material is widely used in the automotive and consumer electronics industry.