brand new and high quality Features: Brake sensing technology, using ARM32-bit processor, shorten the response for time of braking. High-power LED, higher visibility. Built-in 500mAh rechargeable lithium battery, USB type C charging port. Rechargeable, convenient and environmentally friendly Low battery indicator: Battery will be run out in about one hour when the only this LED light on. CNC aluminum alloy shell: CNC process + surface anodized, scratch-resistant, anti-drop. IPx5 waterproof rating design without fear of any bad weather. Good compatibility: square for seat tube, round for seat post, etc. Easy to install and easy to use. Bicycle Rear Light Set only,other accessories demo in the picture is not included. Specification: Battery: 500mAh Rechargeable Lithium Battery Power Supply: USB Charging Flash Mode: 6 Runtime: 8-41hrs Waterproof: IPX5 Material: Aluminum Alloy CNC Size: app.7.85x2.75cm/3.09x1.08in Color: Black Quantity: 1 Set Note: Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Contents: 1 x XfitET 1 x USB Charging Cable 1 x Saddle Mount 1 x Seatpost Mount 4 x Zip-Tie 1 x User Manual