SUPOW&reg; Bike Tail Light, 15 Lumen USB Rechargeable Super Bright LED Taillights Waterproof Flashing Strobe Lights Bicycle Rear Light Cycling Light Waterproof Size: 7.5cm*3.0cm*2.0cm USB Rechargeable battery, automatically cut off when fully charged to protect battery Quick release mount rubber can help you to install it on the mount of bike handlebar, frame, cycling helmets, scooters With 4 light modes - overdrive flashing, Quick blink, slow blink and constant on.