CERAMIC ULTRASONIC AIR TRANSDUCER TRANSMIT RECEIVE PAIR. PANASONIC Part # EFR-TSB40K5 TRANSMITTER, PANASONIC Part # EFR-RUB40K25 RECEIVER 1 OF EACH PER LOT. (If you want 2 pairs, buy 2 lots) NEW OLD STOCK PARTS High Quality bimorph disc type 40KHz Piezoelectric ceramic vibrators. These wide bandwidth ultrasonic transmitters receivers are perfect for robotic projects, alarms, proximity sensors, remote controls, automatic door openers, etc... Transmitter specs: 105dB output (minimum) TYPE 'S' = TEMPERATURE STABLE Receiver Sensitivity = -45dB min. We will gladly combine multiple item purchases to save you money on shipping costs! THIS ITEM USUALLY SHIPS WITHIN 24 HOURS OF PAYMENT! INTERNATIONAL BUYERS WELCOME! WE SHIP WORLDWIDE! Please use the "Ask seller a question" link to ask any questions before buying.