Dodge Raptor Coupling Hub, Tire Rough Stock Bore, E10 Coupling, 2-1/4 in Bore Dia, 3.3 in Hub Dia, 7500 rpm Maximum, 1.88 in Length Through Bore, Steel Suited for any application, hubs are reversible to accommodate a wide range of shaft gapsInterchangeable hubs are used for both close-coupled and spacer designs for reduced inventorySet screw locking mechanism ensures a quick, easy installationTwo set screws at a 65 deg angle optimizes radial and torsional holding power, resulting in a 75% holding power increase versus competitive designs using one set screw