This is M5STACK Ultrasonic Distance Unit I/O (RCWL-9620). UNIT SONIC IO is a GPIO interface ultrasonic range sensor. This module features an RCWL-9620 ultrasonic distance measurement chip with a 16mm probe, which the ranging accuracy can reach 2cm-450cm (accuracy up to ±2%). This sensor determines the distance to a target by measuring time lapses between the transmitting and receiving of the pulse signal, users can directly obtain the distance value through IO control mode. It is ideal to apply in robotics obstacle avoidance, fluid level detection, and other applications that require you to perform measurements.