Velleman ZL388/7 POWERFUL BICYCLE DYNAMO LED LIGHT WITH HOLDER - 3 LEDs powerful dynamo LED flashlight with 3 LEDs soft-touch surface with holder for easy mounting on bicycle cranking for 1 minute will give up to 40 minutes of continuous light weatherproof recommended rotation speed for recharging: 120 RPM dimensions: 2 3/4" x 1 21/32" x 1 21/32" weight: 2.64 oz