These are 19" Chrome Disc Brakes by Pegasus Hobbies.
Suitable for Ages 8 & Older.

FEATURES: Chrome plated plastic construction.
Micro-molded details including calipers.

INCLUDES: (4) Disc Brakes

SPECS: Scale: 1:25
Inner Diameter: 0.13" (3.5mm)
Outer Diameter: 0.53" (13.5mm)
Pegasus Hobbies
Part PGH1093