Type B flange, pilot-bored — meaning it comes with a starter bore (typically 10 mm) that can be machined up to ~42 mm

HRC Couplings are semi-elastic couplings designed for general purpose use. HRC Coupling flanges are available in either F (taper bush fits inside) or H (taper bush fits outside) which permit quick and easy assembly by means of taper bush fixing to the mating shaft. Pilot bore flanges (B) are also available which can then be bored to the required shaft size. Inserts are available in natural rubber for use in ambient temperatures between -50°C to +50°C