APG PRL [PRL-050] True Echo Pulse Radar Level Transmitter, 50ft (15m). The APG PRL series pulse radar level transmitter brings the unassailably accurate level readings of radar sensors to all types of liquid level measurement. The True Echo PRL comes with a variety of housing and antenna materials, and all are IP68 for worry-free operation. True Echo pulse radars also automatically adjusts signal power for optimal accuracy and clarity. With echo masking and damping factors programmable via software, getting dependable level readings from all kinds of liquids is simple.