Weksi Motorcycle Street Bike ATV Rear View Rearview Side View Mirrors 8mm + 2 Handlebar Mount (Pack of 2) Materials: metal arm and plastic frame Dimension: about 21.5x6cm,Mirrors Size: 9.5*5.3cm Suitable for 8mm thread The mirror arm can be rotated This one here, it's a set of 2 side rear view mirrors. Easy to install and very very necessary. Because with bike safety you definitely want all parts in working order. Black side mirrors for 8mm threads, so you just have to glance to the side to see what's behind. Cause when you're going so fast, physically turning your head to behind you is a dangerous thing.