Here is a bike helmet mirror designed to keep cyclists safe on the road. It easily attaches to your helmet in less than 60 seconds. You can mount it on left or right side and make adjustments on the go. The Life On Helmet Mirror weighs only 12g but is sturdy. It lets you see objects behind you without too much fuss. Not too expensive either.
You may want to also check out:
*some of our articles have aff links. Please read our disclaimer on how we fund Exxponent.