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