The REED R5825 is a compact loop calibrator built for sourcing, simulating, and measuring 4-20mA current loops on transmitters, sensors, and valve positioners. It supplies an internal 24V loop power source, reads 0-30V DC and 0-30mA DC, and offers selectable step or ramp output patterns on a backlit 6-digit LCD. A fold-out kickstand and about 20 hours of runtime from 3 AA batteries make it convenient for field calibration work.