Description: 【Smart Programmable LED Expressions】: This intelligent eyes bike tail light features customizable animated displays with preloaded expressive eyes and creative visual cycles. No more boring standard taillights that blend in with traffic. Ideal for cyclists wanting enhanced visibility and personal style 【Universal 30 - 32mm Tube Compatibility】: Designed to fit most round bicycle tubes measuring 30 mm to 32 mm (1.18 inch to 1.26 inch) with 45 degree rotation adjustment. The sturdy mounting system ensures secure attachment on mountain bikes, road bikes, and ebikes 【Rechargeable USB Convenience】: Equipped with a high capacity built in battery that charges via USB cable, providing extended runtime between charges. Delivers reliable illumination for long night rides without battery life. Great for commuters and adventure cyclists 【App Free Use】: Features built in WiFi connectivity that allows direct browser access for uploading custom GIFs, deleting designs, or selecting preloaded options without any mobile app required. No more complicated software installations or compatibility issues. Ideal for tech savvy riders 【Weatherproof Sturdy Construction】: Crafted from quality PC Plastic materials with waterproof that withstands rain, splashes, and harsh outdoor conditions. Maintains reliable performance in wet environments while resisting impacts and vibrations. Great for all weather mountain biking Specification: Material: PC Plastic Size Chart: 9cmx5.9cm/3.54inchx2.32inch Package Includes: 1 set Bike Rear Light Note: Please allow slightly errors due to manual measurement and different monitors.