This mini real light is specially designed for bikes with disc brakes. Just with 2 or 3 magnets installed on the bolts on disc brakes and the light installed between the skewer and the hub, you just need to pedal to generate the electricity through electromagnetic induction.  

Features: 
Mini, reliable and rain resistant.
Specially designed for bikes with disc brakes (The center of the brake should not be made of aluminum alloy.)
No battery required, eco-friendly and energy-conserved.
To adjust the metal clamp to adapt to different bikes.
Easy to install with no tool required.
Note: If you apply three magnets, please make sure one of them is installed in a reversed way for a better lighting effect.

Specifications:
Color: Black + Red 
Light: LED
Material: High-strength Plastic & Stainless Steel 
Item size: 36 * 32 * 25mm / 1.4 * 1.3 * 1.0in
Item weight: 32g / 1.1oz 
Package size: 8.7 * 7.1 * 3cm/ 3.4 * 2.8 * 1.2
Package weight: 45g / 1.6oz

Package List: 
1 * Bike Light