This mounting bracket is made from good-quality Acrylic. It has mounting holes of a diameter of 3.8mm. It is simple, compact, lightweight, and provides more rigidity than most. With this Ultrasonic Sensor Mounting Case Holder, you can attach the HC-SR04 module to your application such as small robots or DIY projects very quickly and conveniently. This module is Only suitable for HC-SR04 Ultrasonic Sensor. This Bracket has a flexible arm and there is no need for any screws to fit the sensor. It fits the HC-SR04 ultrasonic sensor perfectly.