This is Giant's Numen+ Uniclip Taillight which has a 20-lumen output, 5 light modes, a motion sensor, and a neat docking system. You don't have to waste time fidgeting with mounting straps because this light will easily dock into your Giant UniClip compatible saddle with an included fitting piece. The taillight is equipped with a motion sensor. The light will turn off after 5 minutes of inactivity but as soon as it senses movement again it will turn back on. Also, it has a light sensor which automatically adjusts the light (Autoflash mode) depending on the brightness outside, perfect for those early mornings. Note: Only Compatible with Giant/Liv UniClip saddles. Features: Motion sensor Light sensor Low power indicator Auto shut down IPX6 waterproof rating Run time: 5 hours (Eco Steady Day mode) 5.5 hours (High mode) 6 hours (Autoflash mode) 14 hours (Mid mode) 14 hours (Eco Steady Night mode) 24 hours (Flash mode) Specifications: Brightness: 20 Lumens Battery Type: Rechargeable (Micro USB) Run Time: 5 - 24 Hours Beam Color: Red Color: Black Weight: 18g Includes: Tail light Micro USB charging cable UniClip fitting piece