An outstanding value in a quality-built bike safety accessory - compare to similar models at 2-3x the price! Universal fit installs in 30 seconds without tools on any bike handlebar to 1-1/8" diameter; soft rubber liner protects bike finish and ensures secure rattle-free, no-slip attachment. Quick-disconnect feature lets you remove light for use as high-power flashlight or slip in your pocket for safekeeping. Shock-resistant and weatherproof construction with positive-action switch (click-on/click-off) to prevent accidental battery drain. Requires 3 AAA batteries (not included); inexpensive and easy to replace. Dimensions: light 4"L x 1-1/4" diameter, bracket 2-1/4"L x 2-1/4"H x 3/4"W; total unit weight with batteries 3.2 oz.