BICYCLE AND MOTORCYCLE LIGHTS FOR YOUR WHEELS Ultrabright fluorescent colors. Screws onto your valve stem.. Increases nighttime visibility for safety. To replace batteries unscrew plastic top of Fire wheel of wind and remove old batteries.Assemble new batteries as shown then replace plastic top.Screw cap dowm firmly,but do not over tighten. Screw onto valve stem,when wheel is in motion Fire Wheel of wind will then automatically light up! 1.Many colors to choose from. 2.Long lasting replaceable alkaline batteries. 3.Increases nighttime visibility for safety. Battery operation instructions: Red,the yellow uses AG-13 battery blue,green,the purple uses AG-10 battery