RearViz, a device that helps you get where you’re going safely and in style.It is an armband with a rear vision mirror attached. Once you secure the band to your arm, the convex mirror allows you see everything that’s going on in your rear view (hence the name). You can check out the road behind you or oncoming traffic without having to turn your head. Pretty cool. Plus, since it’s not attached to your handlebars or helmet, you can adjust it as you ride.
Features
stylish, lightweight, and comfortable
rotatable base
mirror that pivots 180 dergees 
 
 
Weight:
 85 grams
Washable?:
 warm water and liquid soap
Waterproof?:
 Yes, for short uses though it’s not recommended for constant use in water.
Armband Length:
 The Long armband is ideal for the upper arm / bicep, and the length adjusts between 230mm and 360mm.