When the light is poor, Nite Ize See&';Em(TM) turn bicycle wheels from "hard to spot" to "impossible to miss." Easy to attach and reposition and molded of tough, durable plastic, they&';re backed with stainless steel clips specially designed to snap securely onto oval, round, and bladed (flat) bicycle spokes. A bright, long-lasting LED (powered by a replaceable lithium battery) is activated by a simple twist, and can be seen in even the darkest night to keep you seen and safe while riding your bike. Not only that - when the wheels are spinning, See&';Em create the ultra-attention-getting effect of a moving circle of light. Use one or several on each wheel to create your own signature bands of color.a Bright LED illuminationa 4 pack featuring 2 Red, 1 Blue and 1 Green See&';Ema Twist on/offa Glow mode - compact, convenient illuminationa Battery Run Time: 24 hoursa Includes easily replaceable batteries - CR 927 3V Lithiuma Weather resistanta Easy to attach and remove on most common spoke types - oval, round and bladed (flat)a Product Dimensions: 1" x 1" x .75" (single unit) Weight: .18 oz (single unit)