Fluke PRV240 Proving UnitThe PRV240 is the only battery powered voltage source that can be utilized for verification of your test tool before taking actual measurements when a known source is not available. Verification of your test tool is recommended by both GS38 and NFPA70E before any live measurements are made.Sources both ac and dc steady state voltageWorks with multimeters, clamp meters, voltage testers, and two pole testers.�The Fluke PRV240 Proving Unit is the customer�s best choice because �It is the only electronic voltage source that sources both ac and dc voltages for test tool verification. Competing products offer ramping sources or ac or dc voltage sources, but not both. Competitor�s products require the user to buy multiple proving units to satisfactorily verify all types of electronic test tools.The Fluke PRV240 is used to test both high-and low-impedance digital multimeters, clamp meters and testers. This is important because it provides a stable, fixed output voltage to properly assess clamp meter and multimeter proper operation. Ramping sources cannot be used for these types of test tools.The PRV240 has internal battery power sufficient to perform 5000 verification tests.