I've got them on my MOG, they literally just clip over the top of the screen. Most of the time they are useless as sun visors unless the sun is very low in the sky because the screen is so low.
One thing I did discover was that with the hood up there's a very small gap between the screen and the hood rail and in heavy rain at speed I got unite wet. Must remember to unclip the visors before I put the hood up.
