C4 LED impervious to shock. Will not break or burn out! C4 LED is 2-3 times brighter than previous generation LEDs Features an ultra-bright blue taillight LED Up to 4,500 candela peak central intensity; 80 lumens measured system output 6 hours of continuous runtime to the 10% output level Solid-state current regulation for consistent illumination level Fits both traditional and modern style helmets Tighten clamp with your fingers. No tools necessary! Swivel clamp and insertable 5 angle adjuster to optimize beam location Rotates 360 degrees on clamp Textured parabolic reflector produces a smooth beam hotspot with optimum peripheral illumination Anodized aircraft aluminum Uses two 3V lithium batteries Reflective strip IPX7 rated waterproof to 1 meter for 30 minutes High temperature, shock mounted, impact resistant Boro Float glass lens High impact, chemically resistant engineering polymer LED housing 3.26 in.; 5.14 oz Limited Lifetime Warranty