A micrometric fastener or quick release is also known as a 'Microlock'. It is a popular - because very practical - way to close helmets.
The distinctive ratchet mechanism is the main feature and guarantees a perfect fit every time.

A micrometric fastener or quick release is also known as a 'Microlock'. It is a popular - because very practical - way to close helmets.
The distinctive ratchet mechanism is the main feature and guarantees a perfect fit every time.

You will find this concept on the following pages: