On the digital pins side, it contains 18 terminals: 16 normal terminals and 2 extra GND. As to the Analog pins side, there are 16 terminals (12 normal terminals, 4 extra terminals for Vin, 2*GND and 5V) and 2 breakout through holes for 2 additional ADC pins.
There are many ultrasonic ranger module on the market, but sometimes, these kind of sensor needs to work in conditions more than the Lab. This water proof ultrasonic sensor meets this requirement. It has a good performance and almost the same usage of HC-S04 module.