Highly Customizable Intelligent Expression:244 COB LED lights that you can freely customize;Connect to SageLink APP and draw on your screen freely to easily create your own light style;2 customized emoji: patterns, GIFs. 24 Emojis StorageWT38 intelligent expression tail light comes with 8 preset emojis. It supports up to 16 emojis storage, and it has more than 2 times the storage capacity of other tail lightsWT38 intelligent expression tail light adopts single button design for easy emoji switching with just one press. *Besides the pre-set 8 emojis, all other emojis need to be created by yourself in SageLink APP. Smart Braking SensorWT38 intelligent expression tail light is equipped with a high-precision acceleration sensor that can quickly detect even slight braking and enter a 3-second high-intensity flashing mode. It efficiently alerts vehicles and pedestrians behind you, safeguarding your cycling safety. When you are riding in peloton, this function can quickly prompt the rear riders to slow down in case of an emergency braking. Auto-Sleep & Auto-wakeWT38 intelligent expression tail light supports vibration sensing, and it can automatically enter sleep mode automatically wake up when start moving.