The Gaciron 100 LM Smart Brake 100 Lumens Magnetic Rear Light is a compact, durable taillight with a secure magnetic mount, precision brake-sensing technology, and a wide-angle Fresnel lens for 220° visibility; it includes a long-lasting 420mAh rechargeable battery, CNC aluminum housing, IPX6 water resistance, and convenient saddle and seatpost mounting for safer rides in varied conditions.