I know this won't be news to a lot of people. But have just fitted my first clear insert and it is bloody marvelous !!!!
Not only has it TOTALLY stopped fogging but has also reduced glare and the starburst effect of oncoming lights
I don't usually recommend products but these are a must have for anyone riding this time of year.
£18 inc postage from racevisors if you have a pinlock ready visor. Even worth £40 for a replacement visor if you don't have pinlock ready.