The visual prototype shows the overall shape and size of the product. It does not usually feature any working parts. The materials won’t be the final materials as in mass production. The outer look will remain as the raw material or painted to represent the finished product.
Proof-of-concept prototype shows the key functionality and resolves the main technical aspects of the design. It will make use of existing ‘off-the-shelf’ components, where possible. Therefore, it is not showing the final outlook product.
Presentation prototype shows the key functionality and also provides a representation of how the mass-produced product would appear. The materials will be close to the production grade.