Features:100% Brand New and High Quality..Fits for most type of bikes.Fit bicycle seat post Diameter:20-31.8mmEasy to installation.Beautiful decorations and provide more Safe as rear signal lighting in the evening riding!2 high quality visible red lasers make an instant bike lane for an enjoyable and safe night ride.2 LEDs and 2 laser bulbs， they are work independently.Laser 2 modes: steady—flashing2 LED 7 modes:Mode1:eyes 2 LED constant on;Mode2:eyes 2 LED fast flashing;Mode3: eyes 2 LED slowly flashing;Mode4: left eye，right eye 2 LED flashing in turn ;Mode5: right eye，left eye 2 LED flashing in turn.Mode6: eyes 2 LED flashing flash alternately.Mode7: left eye LED flash twice， and then right eye LED flash twice circularly.Battery:2 x AAA batteries required (Not included)Body color: SilverLight Color: RedSize: 90mm x 62mm x 26mm (approx)Package Included:1 x bicycle laser Tail light1 x Mount Ring