NBK Japan MJB-55-WH 18mm to 18mm Jaw-type Flexible Coupling Automotive bearing this is a popular size

this is a popular size that could be used in many Bicycle or any application that uses this size 12mm

NBK Japan MJS-40CS-WH 12mm to 25mm Jaw-type Flexible Coupling

NBK Japan MJC-95-GR 1 1/4"inch to 32mm Jaw-type Flexible Coupling

which improves precision

NBK Japan MJC-55CS-RD 18mm to 18mm

NBK Japan MJB-55-WH 18mm to 18mm Jaw-type Flexible Coupling Automotive bearing this is a popular sizeNBK Japan MJB 55 WH 18mm to 18mm Jaw type Flexible Coupling NBK Japan MJB 55 WH 18mm to 18mm Jaw type Flexible Coupling NBK Japan MJB 55 WH 18mm to 18mm Jaw type Flexible Coupling, this is a Jaw type flexible coupling. The bellows allows eccentricity, angularmisalignment, and end play. Coupling Bore 1 Diameter: 18mm Coupling Bore 2 Diameter: 18mm Coupling Length: 78 Coupling Outer Diameter: 55 Material: Stainless This is a jaw type flexible coupling.