http://www.ht-instruments.com/en-us/products-ht/multifunction_installation_testers/combi421
Continuity test with 200mA
Insulation with 50, 100, 250, 500, 1000VDC
Trip out time of RCDs type AC, A Standard and Selective up to 1A
Trip out current of RCDs type AC, A Standard and Selective up to 1A
Line/Loop fault impedance
Line/Loop impedance with high accuracy (with IMP57 optional accessory)
Prospective short circuit current
Contact voltage
Global earth resistance without RCD tripping
Phase sequence indication
AUTO function (Ra + RCDtest + Insulation) on plug
AC TRMS voltage and current
Active, reactive, apparent power and power factor on single phase system
Harmonics voltage/current up the 49th and THD% on single phase system
Environmental parameters measure (°C, °F, %RH, Lux)
Measure with remote probe (with PR400 optional accessory)
Leakage current
Data HOLD
Help at display
Internal memory
Optical-USB interface with PC connection