This cage comes as an upgrade to the 122mm CV joint our Half-Shaft kits use. It`s tested to swap the OEM cage of the following CV joint part numbers: Mercedes OEM: 6383342334 GKN/Spidan/Lobro: 0.021727 / 303540 SKF: VKJA 8608 Audi: 7L6407331A GKN/ Spidan/ Lobro: 0.024464 / 304737 In depth product desctiption: This product is manufactured from Carburized Steel, the premium choice for drivetrain components requiring a balance of extreme surface hardness and internal toughness. Case Hardened Surface: Through advanced carbon diffusion, the outer shell reaches a hardness, providing industry-leading resistance to wear and "notching" caused by ball bearing contact. Shock-Absorbing Core: While the surface is rock-hard, the inner core remains ductile and flexible. This enables the cage to absorb violent torque spikes and heavy impacts without catastrophic fracture. Superior Fatigue Life: Carburizing induces compressive surface stresses that inhibit crack initiation, ensuring long-term reliability under the most demanding racing or off-road conditions. You can see more on the topic in the following YouTube Video: https://www.youtube.com/watch?v=bjylvXwV5lY