2pcs Bicycle Handlebar Mirrors, HD Acrylic Convex Rearview Mirror 360° Adjustable Handlebar Mount with Allen Wrench

The inner aperture is17.4mm/0.69in-22mm/0.867in Can only be used within the range

Self-fixed simple rearview mirrors for bicycles can be directly installed on the handlebars or auxiliary handlebars of various bicycles without the need for additional acssories. After installation, in some cases, the rider's body or arms may block the view while cycling. When you need to see through the mirror, you can just shake the front of the bicycle to adjust the angle of the mirror.