HOW THEY WORK!
Basically the visor insert is constructed out of the same vinyl film they use to create the advertising you commonly see on bus, car, and shop windows. You know the type that allows you to see through the window from the inside, but allows the advertising to be clearly visible from the outside. Example of this is below.
It is essentially a thin film with tiny perforated holes punched in its surface to the ratio of 50% material to 50% hole area. The film is black on the helmet inside surface, and because the interior of the helmet is dark anyway, and you are so close to the film your eyes cant focus on the film itself and so see the outside image instead. Gives a tinted visor type view.
This is attached to a flexible transparent sheeting which is mounted to the inside of the visor with `Velcro` type fasteners for easy fitment and removal. This also stops any contamination by dirt/water into the perforations which would obscure vision. Hopefully the pictures below of my helmet make this clearer.
Visor Insert Assembly
Perforated film mounted on flexible clear backing with `Velcro` type fastners for easy fitment/removal .
View through Visor
Attempt to photo view from inside helmet! Actual view is much better, as inside of helmet is darker than my sittingroom so cant see dots! Tinted visor type view.
Helmet with visor insert removed
Weather conditions too bad? Heavy rain/overcast/night riding? Simply remove visor insert for clear original visor!
And now for the legal stuff! Here in the UK the legal legislation requires that motorcycle helmet visors comply with the EC regulation 22.05 or British Standard BS4110:1979 (as amended). These standards currently allow visors intended for `daytime use` to have only a moderate tint with a minimum light transmittance of 50%.
For legal reasons I sell these helmets on a strictly ` NOT FOR ROAD USE ` policy! If you use the helmets on the road instead of for shows / display with the visor insert in place it is your decision only! I will not be held responsible if you crash or get arrested, etc.
If you want to use these helmets on the road legally, simply remove the visor insert!
Not all countries / states may have the same legislation. It is solely up to you to ascertain the legalities of using visor inserts where you live / ride.