THE REVO READY LIGHT MICRO GRAY IS THE PERFECT MICROLIGHT TO ADD TO YOUR GEAR! WITH A 100 LUMEN OUTPUT AND AN EXCELLENT RUN TIME, CONVENIENT RING ATTACHMENT FOR YOUR KEYS OR OTHER ATTACHMENT POINTS, ITS READY TO GO WITH YOU ANYWHERE. ITS EVEN WATER RESISTANT TO THE IPX8 STANDARD! ---Uses (3) LR44 Button Batteries (included) --Claimed 16 hour runtime --Light approx 1 1/4" long.