The main material of diecast models is a zinc alloy called Zamak.
A model could conceivably be made in any scale, but the market usually dictates the scale. Construction equipment models are most often 1:50 scale; farm equipment models are most often 1:32 scale or 1:64 scale; automobile models are most often 1:24 or 1:43 scale; models made to fit into the most common type of model railroad layout, HO gauge, are 1:87 scale.
The British and Germans, and to a lesser extent the Americans, pioneered the manufacturing of diecast scale models, beginning in the early 20th century. Within the past 20 to 25 years, virtually all diecast model manufacturing has migrated to factories in China.
The molds for today’s diecast models are typically created from the same computer-generated design files as manufacturers use to make their real machines and vehicles resulting in very high levels of detail and realism.