Description: 10mm 40KHz Transimitter Receriver 2 in 1 Ultrasonic Sensor Transducer Construction: open structure type? Free Capacitance: 2200 ±20%; Min. Sound Pressure Level: ?100db Impedance: 800Ohms Material: ABS; Center Frequency: 40 ±1 KHz Size: ?10xH7 mm/ ?0.39xH0.27 inch Package Includes: 1 piece Ultrasonic Sensor