Most clear and amber polycarbonate visors and drop-down sunscreen visors are about 96 to 98 percent UVA and UVB blocking. Most tinted and mirrored visors are 100 percent.
I’ve recently become infatuated with Transitions or adaptive face shields. They aren’t cheap, but it eliminates the day to night problem with a single shield.
As a side note; dark tinted or mirrored visors for motorcycle helmets are illegal in Thailand. The rule is that the police must be able to see a rider’s face at all times while riding on the road.
Anyone caught by police wearing a helmet with a tinted visor – or found to be riding without fastening the chin strap or not wearing a helmet at all – faces a fine of up to 500 baht
I’ve always used tinted visors for my full face helmets and wondered what the UV ratings would be for the various tints available for most motorcycle helmets like smoke, amber, chrome? My current helmet has a build-in sunscreen visor that flip down from inside, which are convenient in not having to carry extra shields in in an old sock.