What is the Difference Between Flock and Flex Films?

What is the difference between flex film and flock film?

Flex films are thin textile transfer films, usually made of polyurethane, with a slightly rubbery appearance.
Flock films are thicker and have a velvety surface.
Flex films are more durable and stretchier than flock films, which gain their tear resistance from their attachment to the textile.
Flex films are suitable for smaller lettering, whereas flock films are not.