The PRBIII is a solid cast TNT antitank mine. No paint, no markings.
Only the fuze has plastic components.
An anti-lifting device is set on the base.
The fuze on this A/T mine is almost identical to the fuze on the M35 A/P mine.

Height: 104mm , diameter: 229mm.
Weight: ? gram. Filling: 10kilo TNT.