When the light is poor, Nite Ize See'Em turns bicycle wheels from \ "hard to spot \" to \ "impossible to miss. \" Easy to attach and reposition and molded of tough, durable plastic, they are backed with stainless steel Steel clips specially designed to snap securely on 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 even in 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. Features: - Each package contains two See'Em LED Mini Spoke Lights - Bright LED illumination - Twist on / off - Glow mode - compact, convenient illumination - Battery Run time: 24 Hours - Each See'Em includes replaceable 1 x 927 3V lithium battery - Weather resistant - Easy to attach and remove on most common speech types - oval, round and flat - Product Dimensions: 25 x 25 x 20 mm (single unit) - Weight: 5g (single unit) - NOT FOR USE WITH CARBON SPOKES