Review on KTM OPEN COMPOUND GRIPS 63002021200 by Victor Ceja

They work great with the Duke 390, I have them on my bike. The only thing to note is that they don't fit the stock gas tube, so you'll have to buy one or use the one on the bike and sand it down with 60 grit (strength) sandpaper. It also reduces the radius of rotation of the throttle, making the throttle slightly shorter, so keep that in mind. Personally, I don't find much of a difference, and I enjoy practicing throttle control this way.