HC-SR04 Ultrasonic Sensor,LGDehome Measuring Distance Sensor Ultrasonic Transmitter and Receiver Module for Arduino UNO Nano Robot XBee ZigBee (Pack of 10)

These arrived in a timely fashion and performed as advertised.

Pleased with these sensors. I am using them in an array where I need to read all 10 in series and they are accurate within +/- 1cm with the Arduino library I am using (this specific library doesn't resolve below 1cm so there is likely more precision there). No dead units or issues with distance timeout lockup that some users experience with these types of units.

Bought a batch of 10. None work. Not reliable. Stay away from this product.