This kind of wheel spoke light can effectively warn others to protect your safety. Shows your unique personalities and cool at night It can be fixed on all kinds of bikes! Super bright 8 LEDs design and not affect the bike center gravity 3 Functions: Quick-Slow-Steady Can be fixed on any cycle hub with diameter no more than 35mm Easy to install,no tool in need Waterproof,can work in rainy day but not soak in the water Specifications: Work time: 12 hours Hub diameter: 19mm - 36mm Mode: steady, slow flashing, quick flashing Power type: rechargeable Li-Battery PACKAGE INCLUDE: 1 x Bicycle hub light 1x User manual 1x USB charging cable NOTE: 1.Due to the difference between different monitors,the picture may not reflect the actual color of the item. We guarantee the style is the same as shown in the pictures. 2.Due to the manual measurement and different measurement methods, please allow 1-3cm deviation.Thanks!