Compact USB rechargeable front light with a powerful brightness of 300 lumens. Equipped with a "brightness adjustment" that allows you to choose the brightness you desire, and a dayflash mode for added safety. 1 x 3W White LED Li-Ion Polymer Rechargeable Battery (DC5V/0.5mA) Charging Time: 2.5 hours Battery Capacity Indicator Low Battery Indicator Illumination / Boost On/ High Brightness On/ Pulse On/ Day Flash: 8 hours, Boost Illumination: 4 hours, High Brightness Illumination: 2 hours, Pulse On: 8 hours, Dayflash: 3.5 hours Brightness Adjustable. Illuminated: 1 - 8 The lighting time will vary depending on the brightness set the time. Includes 1 USB cable (mountable diameter): Φ0.7 - 1.9 inches (18 - 48 mm), L2.4 x W1.3 x H1.0 inches (57 x 32 x 25 mm) (light body) 1.9 oz (53 g), the color of the product may look different from the actual product Product specifications, logo design, etc. may be subject to change for product improvement. We also cannot answer measurements or personal fit that the manufacturer does not announce.