TO ACTIVATE: Unfasten & pull apart the metallic base. Remove the white paper strip from between the batteries & the light. Re-fasten and then attach to your tire’s valve. Then ride! The little light will do the rest. The Flashing Valve LED Bicycle Lights for Tires operate upon movement. ONLY ONE FUNCTION: Color changing upon motion! NOTE: There are two lights per pack–Meaning when you order 1 pc. you are getting 1 pack (2 lights) Dimensions: 2.5 in. long LEDs: 1 Purple, 1 Yellow, 1 Red, 1 Green, 1 Blue, 1 White Batteries: Includes 2 Replaceable AG10 Batteries