VICTOR 4109 VC4109 equal potential bonding resistance tester L Apply to measure equal potential bonding resistance of buildings'metal and resistance between electrical device and earth mat 'pole.And measure measure resistance of switch or socket, as well as low resistance L Measure range: 0.020-1999, resolution: 0.001, precision: 2% L Interference voltage (UST) range: 0-50V (AC 45-400HZ), precision: 5% L Adopt DC voltage energize and change pole to measure automatically (4pole or 2pole) L Maximal open circuit voltage 20V, short circuit current L can dislodge surplus resistance of measuring wire L can store 100 (Group) measured data L Employ instrument panel calibration technology