1. Product Overview 31308A-DF-A50-90 is factory pre-matched double 31308A single row tapered roller bearings arranged in DF face-to-face (X-type) configuration. A = reinforced high contact angle design for greater axial load capacity DF = Face-to-face matched assembly A50-90 = standardized spacer / mounting dimension designation for original equipment interchange This matched set simultaneously bears heavy radial load and bidirectional axial thrust, improves system rigidity