The Fluke 707 Loop Calibrator is a high performance solution for calibration, repair and maintenance of current loops. The new " Quick Click " knob making it extremely fast and easy to use. It features: 
One handed user interface with " Quick Click " detented knob
mA sourcing, simulation and measurement
0.015% accuracy and 0.001 mA resolution
Simultaneous mA and % of span display
Selectable step or ramp outputs
24 V Loop supply with mA measure, including 250© HART resistor
0-28 VDC measurement to check Loop Voltage
Easy battery exchange without opening the case
Compact case with separate protective holster
Three year warranty

Features: 
The fast, one-handed tool for loop checks. Just click to calibrate.
This feature-rich solution combines the best features push-button and knob-base loop calibrator and offers: 
Large display and simple, quick-click interface for easy one-handed operation
Simultaneous mA and % readout for quick, easy interpretation of readings
mA accuracy of 0.015% , superior to other loop calibrators in this price range
1 µ A resolution for mA source, simulate and measure
Push button 25% steps for fast, easy linearity checks
0-100% “ span check” for fast confirmation of zero and span
Selectable slow ramp, fast ramp, and step ramp to provide smooth outputs for valve slewing and loop functional test
24 volt internal loop supply, so you can power and read a transmitter at the same time without carrying a DMM
Measures V dc to 28 V
Single 9V battery that is easily changed without braking calibration seal
0 - 20 mA or 4 - 20 mA default start up modes
Innovative output adjustment dial with 1 µ A and 100 resolution
HART mode connects 250 O resistor in series with 24 V loop for compatibility with HART communicators