What is a Dual side mirrors?

1. for a car/truck, you can either purchase a full pair, or the circle ones that stick on your car window. not only does it help for use of a blind spot (mostly with trucks) but its the state laws now to have them on your mirrors if your back window on your car is tinted 25% and under. they say its so you can see 1/4 of the car that's driving behind you.

2. A make up case that has two sided mirrors