Keeping rain off your visor 
By andybiker -
Helmets
26 May 2009 12:05
Regarding keeping rain off your visor, the best way is to use a V-Wipe. No, not the sponge in a bag that helps you keep it clean but a rubber sheath complete with windscreen wiper-like blade that you slip over your gloved finger.
I think it's made by Bob Heath. Brilliant!