Are they not on sale anymore? I see them on ebay for about $22 shipped. I've actually them saved in my ebay because I've been planning on buying one. Haven't gotten to try one yet but I'll grab one before spring so I can see how well they do. My XB is by far the loudest bike I've owned so far, both exhaust as well as wind noise so I'm up for trying anything.
Those ones are made my speedmetal. I wonder how they compare to the Proline version. The proline looks a little nicer, but it's a pretty simple idea so I doubt there's much difference. I'll try to find a review of this one and buy one this weekend.
I kindof hate mine. It reduces a little noise, and makes it warmer in your helmet. But forget about breathing with the visor down. Which means you'll need to open your visor at slow speed and stop lights.
It's neoprene with a reusable sticky ring around the inside. You're supposed to be able to remove it and reposition it, but I doubt it lasts forever like that. When I get one it definitely wouldn't be on all the time. If the sticky stuff wears out I'm sure there are ways to get it to hold well again. I have a bigger version that sticks around the bottom of the helmet but actually goes down around your neck to your shoulders and I've put it on and taken it off 100 times. Not the same brand though so I'm sure it's a different way of making it stay in place.