Ultrasonic Sensor Mounting Bracket for HC-SR04 Smart Car Material: imported acrylic Application: Stationary ultrasonic sensor modules and other products; This bracket can only match HC-SR04 ultrasonic ranging module, the other ultrasonic modules can not support Thickness: 2.8-3.1mm Inside diameter: 16mm Mounting holes diameter: 3.8MM Material: transparent acrylic Applications: stationary ultrasonic sensing module Package Included: 1 x Ultrasonic Sensor Mounting Bracket for HC-SR04 Smart Car AL