Suitable for diameter: headlight 3.2 cm diameter, tail light 2.5MM inner diameter Material: high quality engineering plastic + waterproof rubber gasketSpecifications: headlight 0*6.5*3.3 taillight 6.5*4Instructions for use: One-button control switch on the back, and a clip (clip) on the back. It can be clipped on bicycles, belts or shoulders or backpacks, school bags and other personal items, and it plays a safety warning role to ensure personal safety.The flash mode is: Click: 5 lights longSecond: 5 lights flashed quickly Third: 5 lights are slow and flashingFourth down - seventh down: 5 lights rolling flashing in different directions Eighth: Close