This hub has a 15mm bore, 5mm keyway, 75.0mm OD, and 18.0mm length.
Controlflex Coupling Hub w/Key, Double, Bore 15mm, OD 75.0mm, Alum It has a balanced design and can accommodate speeds of up to 7500 RPM. The use of a keyway prevents the coupling from slipping on the shaft if over torqued. Ruland supplied Controlflex couplings are a lightweight, low inertia, and zero-backlash coupling designed for use in encoders, tachometers, resolvers, and light duty power transmission applications.