You need for installation variant C:
Narrow helmet adapter
TILSBERK Head-Up Display
TILSBERK Head-Up Display App
Adhesive pad for narrow helmet adapter
For which helmets is installation variant C suitable?
Installation variant C is often used for helmets with a sun visor whose fabric in the area of the mounting surface (marked red) is fixed / not stretchable.
Note
Before installation
To ensure secure attachment, all adhesive surfaces must be clean, dry and free of dust and grease. Therefore, please clean all smooth surfaces thoroughly with an alcohol-based cleaner such as white spirit or rubbing alcohol before mounting. Adhesion is better on surfaces made of fabric - however, these surfaces should also be cleaned.