Bearing bird cages are manufactured from rigid billet aluminum and are fitted with heavy duty roller bearings. Bolt together design allows repairing rather than replacing. Off ered for most popular racing chassis, bird cages may be fitted with brake floating option or rotating shock mount. Bird cages are not equipped with caliper brackets.Pit Stop USA offers PPM Billet Aluminum Bearing Bird Cage Kit (Pair) Mastersbilt 2500B-MB at low everyday prices. Be sure to check out all of our products from PPM Racing Products including PPM Racing Products PPM Billet Aluminum Birdcages.