CNC-machined lightweight aluminum main Axle includes factory-pressed (non-replaceable) high-quality German one-way bearings, hand-ground for Maximum running precision and strength. The one-way bearings must be serviced, cleaned, and oiled regularly (we recommend using #309580 One-way Lube). Fits #305104 Multi-Diff™ for XRAY T2'008, T2'009, T3 only.