Size 304 Disc Coupling, 9" Outside Diameter, 4.5" Max Bore Size, Style KD21, Rough Bore, Non-Lubricated Spacer coupling with economical 3-component design. Unitized Disc Packs for ease of maintenance, replaceable without moving the connected equipment. HT (High Torque) disc packs for medium and heavy duty applications. Meet AGMA Class 9 balance off the shelf. Balance to AGMA 10, or compliance with API610 are available options.