I have the Cee Baily, light smoke deflectors, and stock windshield. I put them on for cold weather, and take them off for warm weather. They do a nice job of deflecting much of the lower air, that the windshield does not. If I recall correctly, this would be from upper legs, to lower stomach & sides. Certainly keeps me warmer in cold temps. The Cee Baily's are somewhat larger than the Yamaha ones, but I never tried the Yamaha ones, so can't really comment on them.