This ultrasonic sensor uses the exact same Arduino library as the HC-SR04. This sensor was originally designed to be installed in a vehicle as a parking sensor. The ultrasonic transducer is waterproof.Specifications:Operating voltage: DC 5VCurrent: 40mAAcoustic emission frequency: 40khzMax distance: 4.5mBlindspot: up to 25cm70 degree detection angleRecommended installation hole: 20mm diameterSensor Cable length: 2mWiring:+ 5VDCTriggerEchoGNDPackage Includes:1 x DC 5V Waterproof Ultrasonic Module and Transducer