ITEM NO:   US-2  PRODUCT NAME:   "AL" Brand Ultrasonic Sensor Click here to enlarge the photo.   "AL" Brand Ultrasonic Sensor Transmitter / Receiver / Combined with Waterproof Type Aluminium Case, with Pin Dia. Range from 10mm to 25mm Height Range from 12 to 22.5mm Frequency: 23/25/33/39/40 KHz [Previous Item] [Next Item] To make enquiry on this product, check the box and click .