LCR meters are typically used for component testing.  This one does not have connectors for the test port but rather a built-in fixture to test leaded components.
The SR715 is the low end LCR meter in the Stanford Research LCR meter line and the SR720 is the high end unit that includes a 100 kHz test frequency, GP-IB, RS-232 and Handler interface.  The SR715 has just the RS-232 interface and only goes to 10 kHz..

May be the basis of the HP 4263A LCR meter.

Test frequencies: 10 kHz, 1 kHz, 120 Hz or 100 Hz. 
The upper two frequencies are typically used to test audio components and the lower two for testing power supplies that work from 60 or 50 Hz mains.
Equivalent Circuits: R + Q, L + Q, C + D, C + R
The last circuit (C+R) may be good for estimating the ESR of caps.
Drive Voltage: 1.0, 0.25, 0.10
The lower drive voltages are handy when testing things like diode capactance, i.e. to keep from turning on the diode.

The on line manual is missing the schematic diagram.  For that you need to purchase a manual from SR.

SR727 SMD Tweezers
SR726 Kelvin Clips
SR728 BNC Fixture Adapter

Test Equipment
HP 4260A Universal Bridge
HP 4332 HP 4332 LCR Meter
HP 4395A Combined Network, Spectrum & Impedance Analyzer
Impedance - in general
TF2700 Marconi TF-2700 Universal Bridge
Zo Transmission Line Impedance (is not constant with frequency)
ZM4 - DC Bridge
ZM-11 - Capactance-Inductance-Resistance Bridge
EVB ESR Tester
ESR-micro v4.0 ESR Tester -