[4 Lighting Modes & Adjustable Brightness] This bike alarm tail light has 4 lighting modes, normal flash/breathing flash/quick flash/steady on, you can use the remote control to change the mode you like, or just press the tail light button on the bike to switch the mode. The brightness is adjustable, in always-on mode, long press the button to adjust the brightness you want. [Anti-theft Alarm Bike Tail Light] The bike security siren can emit a loud sound (105~115 decibels) to attract attention and deter thieves. Open distance, remote operating distance up to 50m (164ft), easy to find your bike's position by light or sound. Note that it does not include a GPS tracker. [SMART BRAKE SENSING] Designed with a brake sensor, the super bright automatic brake light will automatically turn on after braking. The bike lights are super bright and visible from a distance, really attracting attention to increase your safety. The brake sensor function is available in all lighting modes.