This little laser beam tail light will ensure your safety while riding in the darkness. It has 5 LEDs and 2 laser bulbs. The LED and the laser work independently This safety light can be mounted on 20-36mm seat post. The length and position of the laser beam varies with the angle you mount the lamp 7 kinds of flash mode: Always bright, flash, slow flash, left to right, right to left and left to right slow flash, flash, flash back and forth 2 laser lights remind someone else of keeping distance, add safety.This little laser beam tail light will ensure your safety while riding in the darkness. Note : Do not look directly at laser lights Waterproof, safer in water fog when riding in the rain Use for jogging, walking, bicycles, car emergency, horse-riding, road emergency & camping, ETC. Working time: About 9hours Specifications: Working: 9-36 hours depends on the batteries Power: 2 x AAA batteries (not included) Material: ABS, Acrylic & Nylon For 20-36mm tube Input Power: 1mW WARNING: LASER RADIATION AVOID DIRECT EYE EXPOSURE! KEEP OUT REACH OF CHILDREN! Package: 1 x Bicycle Laser Beam Rear Tail Light Lamp 1 x Bicycle Mount