Caberg Avalon | Avalon X Visor Antiscratch Fogcity Ready From  £43.99

I bought the dark smoked visor because the built in sun visor has too much distortion and is useless !

Fit is perfect and once you figure out the correct way to attach it to the helmet it is very simple, you have to get the little retaining clip behind a little rail on the helmet to fit it.
Visibility is perfect and it's not quite as dark as it appears but it does filter out strong sunlight effectively.
Only 4 stars because it's very expensive but necessary !