Funny you should ask but my missus spotted one on a Harley just the other day and commented on it. My opinion, it looked both silly and dangerous. These backrests are not really backrests, they are too short for that, they are more like lumbar supports. As such I'm not sure they would do much good from a comfort point of view on a proper tourer like ours, (OK on a Harley where you are almost laying down I suppose) and they would certainly make the pillions job of actually getting on far more difficult.