Model: TCT40-18R - Color: Silver - Material: Metal - Nominal frequency: 40kHz - Transmit sound pressure at 10V (0dB=0.02mPa): >= 110dB - Receive sensitivity at 40kHz (0dB=V/ubar): >=65dB - Static capacity at 1kHz - Pin patch: 1cm - Application: Ultrasonic remote control device for home appliances and other electronic equipment; ultrasonic ranging and auto reverse anti-collision device; liquid level detection; ultrasonic proximity switches and other applications ultrasonic transmitter and receiver - Great for DIY project - Comes with 1 pair for one package - "R" is receiver head "T" is transmitter head