Bicycle rear light battery with high quality lithium battery, the service life can be guaranteed. Led bike taillights are made from US CREE LED to get the best value between the brightness and energy loss for money. The light 220 horizontally and 20 vertically, it shines over the road and thus ensures more safety and you are quickly noticed by other road users. Patented "S" hook for quick and easy assembly / disassembly, no tools required. Suitable for most handlebars, as well as with seat posts and frame tubes. With IPX4 high water resistance. It can be used on rainy day. Specifications: Light color: red Material: ABS + rubber Weight: 24g 62.4mm43.4mm37.7mm(L * H * W) Battery: 2CR2032(not included) Gear position: always on/flashing/breathing Illumination angle: horizontal 220/vertical 20 Charging time: 2 hours Waterproof: IPX4 Installation steps: Step 1 Place the rear light on the seat post in a suitable position. step 2 Use the "S" hook to tighten the taillight. step 3 Make sure that the hook "S" is fixed. Step 4 Finished! Package includes: 1x rear light