Suitable for installation to handlebars and rear-view mirror frames or other round rails within the stated dimensions. Accommodate round rails 0.5 to 1.26 in diameter. Package come with three soft rubber ring inserts to provide a snug fit and protection of the mounting surface. Three rubber ring diameter: 0.5, 0.87, 1. Mount base diameter: 1.26( when without sizing inserts ). Suitable for installation on bike, bicycle, motorcycle, stroller, mountain bike, dirt bike, trek bike, road bike, golf cart, electric scooter, ATV, etc.