Other mirrors are too small or not sturdy or have too much road vibration to be useful. Have bought these for myself and my partner, we're very happy with them. It feels so much safer to ride roads with a mirror!
I have had to discontinue attempts to use this product. If you wear glasses for reading , the combination of the distance that can be achieved with the telescoping arm and more importantly the curved mirror it is almost impossible to focus and see approaching rear traffic. Additionally I would not recommend trying to attach to the Kask mojito helmet as the helmet has much narrower and fewer flat planes for the adhesive to stick to.
While many of the features of the selfie are good I'm marking it down because it doesn't allow a clear image of what's behind. If MSW would make a flat 1.5-inch replacement mirror that would solve the problem of convex mirror not being able to give clear image rearward.
It seems reasonably good as long as you have some flat (or almost flat) place on your helmet. I could not find any place on mine so will be returning it.