Universal Design: Suitable for any car, SUV, truck. Wireless design, no damage to the original car wiring, just stick it on the car door. Pay attention to how it works. When the door is opened, the blue light will flash to warn pedestrians or rear vehicles to avoid an accident or collision. 3 Flashing Modes ----- 0-7 sec. All LEDs flash quickly. 7-60 sec. 7-60 sec: Each LED flashes sequentially. 60-110 sec. Each Led flashes slowly while rotating. 110 sec. Auto power off. Waterproof Design: Immersed in water for 30 minutes and still works. High-tech component detection: Controlled by infrared chip program to improve sensitivity and maintain product stability. Long battery life: This product uses CR2032 button battery (battery is included), through testing, under normal operating conditions, can be used for 1-1.5 years, screw cap design, you can easily replace the battery.