Fog City – They stick on and work very well, but can be tricky to install (You only get one chance) I’ve used them on various Arais for years, and I used to ride all through the winter
http://www.phoenixnw.co.uk/fogcity.html
Pinlock – Just clips in but you need to have the pins alrady in your visor for it to clip to (I think you can install your own though) They are removeable/interchangeable which is handy. My new lid is a Shoei XR1000 which came with one supplied. It seems to work the same as a Fog City, but I’ve not used it in foul weather yet (Fair weather biker these days!)
http://www.phoenixnw.co.uk/pinlock.html
Actually, looking at it now, they don’t seem too expensive. 🙂