In Pixar's Cars, which vehicle model is Mater based on?

In Pixar's Cars, Mater is based on a 1951 International Harvester boom truck.

Mater is Radiator Springs' rusty tow truck and Lightning McQueen's closest friend. His design is intentionally weathered, with a missing tooth, mismatched appearance, and visible wear that distinguish him from the polished race cars. The International Harvester boom-truck basis gives him the tall, work-oriented shape associated with older utility vehicles.

Mater's exact mechanical identity is sometimes simplified to “old tow truck,” but that description leaves out the specific model reference. He is not modeled as a modern roadside-recovery vehicle, and he is not a pickup truck merely carrying towing equipment. His crane and rear towing apparatus are central to his silhouette.

In Cars 2, Mater becomes unexpectedly involved in an international espionage plot, while the animated series Mater's Tall Tales exaggerates his storytelling. Those adventures do not change his original character design or his role as Radiator Springs' local tow truck.