copy from their web site.
Wavetrac® At A Glance:

• Innovative:
Patent pending Wavetrac® design automatically improves grip in low traction conditions. This feature is truly innovative and unlike any other torque biasing diff design.
• Superior Materials:
9310 steel gears run in case-hardened billet steel bodies. ARP® fasteners used throughout.
• Maintenance Free:
As supplied new, the Wavetrac® differential will perform a lifetime of service without maintenance or rebuilds.
• Customizable:
If desired, you can alter the diff’s behavior to suit your needs using optional components.
• Limited LIFETIME Warranty:
All Wavetrac® differentials include a transferable, Limited Lifetime Warranty.