Megger MPU690 Proving Unit
Good practice requires that two-pole voltage detectors are proved to be functioning correctly on a known voltage source, both before and after they have been used to verify that a circuit is not live.
Megger MPU690 Proving Unit features:

5 stepped nominal output voltages
Automatic operation
High output power suitable for test lamps
Extended battery life
Magnetic base
Rugged case

The Megger MPU690 proving unit provides a portable battery-operated voltage source that can verify the correct functioning of two-pole voltage detectors. The device safely generates a range of voltages from 50 V to 690 V in five steps. At switch-on, the unit initially generates 690 V then, after a short period, slowly ramps down through each voltage step until the device switches off.
The individual voltage steps are indicated by an LED. It also has an LED to indicate when the power is on and when the battery is exhausted. It is worth noting that while the unit has a high output, the unit has exceptionally good battery life.
The Megger MPU690 features automatic power-on when voltage tester probes are inserted into the output terminals, generating a 50 Hz output voltage which simulates the AC mains supply.
The generous output power rating and the spacing of the output terminals allows the MPU690 to verify the correct operation of voltage indicators that utilize a lamp for operation. Additionally, the rugged case of the Megger MPU690 features a magnetic base for convenient use.
Please note that the Megger MPU690 is not recommended for use with multimeters.