Model Board is also known as Styling Board or Tooling Board and used by manufacturing companies to make prototypes. It comes in various densities and can be hand carved or machined but the higher the density of the board the harder it is to work by hand.
Catering for a lot of a modellers needs it is very easy to work with and can be carved into, cut with a knife or a saw or drilled, it takes super glue very well allowing a variety of items/objects to be stuck to it as you build your model.
Model Board is essentially a combination of epoxy resins, glass micro-balloons and hardeners, which are mixed together and cured in an oven until hard.
This can be a very dusty material to work with and goggles and a dust mask are recommend when sanding or cutting this material, not recommended for children under 14 years of age.