Martindale PD440S Proving Device  
Safe electrical working requires the use of a voltage indicator that has been proven with a suitable proving device before and after use to ensure the instrument is working correctly in accordance with the Electricity at Work Regulations.
With all the benefits of the industry standard Martindale PD440 and PD690 proving units, the S models come in an overmoulded low profile case with magnetic hanger.
They are fast and easy to use, instantly supplying the full test voltage for both high and low impedance voltage indicators, test lamps and meters.
The SRDX model has a unique CALCHECK feature making it easy to verify the
insulation and low resistance ranges on 18th Edition multifunction testers, wherever you are working. In addition, the new SRD and SRDX models have stepped voltage LEDs with thresholds matched to most voltage indicators and two pole testers.
Key features
Ideal for proving low and high impedance voltage indicators, test lamps and two pole testers
Includes MG3 high strength magnetic hanger
Colour coded for voltage output (230V, 440V and 690V)
Tough overmoulded low profile design
Long battery life with low battery indicator and auto power off