Description: Material: The CB-18046 Smart Bike Tail Light is made of sturdy ABS plastic shell with COB lamp beads, ensuring a strong design that can withstand outdoor cycling conditions.Multiple Modes: This rear bike light features four different modes - breathing mode, slow flashing mode, fast flashing mode, and constant light modes - allowing you to adjust the lighting according to your needs and safe requirements.Compact Size: With dimensions of 2.76inchx1.38inchx2.76inch, this Brake Sensing Bicycle Rear Light is compact and lightweight, making it easy to install on any road or mountain bike.Features: In breathing and slow flash modes, the Bike Tail Light Smart will automatically turn off when it is still for 30s, and will automatically turn on when it feels vibrations. IPX5 Waterproof.Easy Installation: The Cycling Safe Accessory is easy to install, no other professional skills are needed. Specification: 7cmx3.5cmx7cm/2.76inchx1.38inchx2.76inch Size Chart: Battery capacity: 300mAh Package Includes: 1?Smart Bike Tail Light Note: Please allow slightly errors 1-2cm differences due to manual measurement.