Surface-mount drive electronics now reside on the 600 series of smart ultrasonic sensors. The units, which have 50-kHz electrostatic transducers, are compatible with transistor-transistor logic and feature a beam angle of 15° at −6 dB. They include convenient pin terminal connections, have monostable and astable operating modes, are voltage-regulated for 6- to 30-V dc operation, and feature low ring characteristics. Instrument-grade (PID#615088), environmental-grade (PID#615089), and open-face type (PID#615090) units are available for sensing ranges from 6 in. to 35 ft. Pricing starts at $45 each in quantities of 10 and $35 each in quantities of 100.