This instrument applies DC voltage converter with low loss, high variation ratio, and inductive energy storage, which can convert 9V voltage to 250V/1000V DC voltage; it applies digital electric bridge to measure insulation resistance; it has functional characteristics of portability, wide measuring range, backlight display, and data holding; it can measure electric supply as well. When using straps, the operator can operate the instrument with both hands. The instrument has a fashionable appearance and stable performance. It is suitable for measuring electrical machinery, cable, electromechanical equipment, telecom equipment, electric power facilities and other insulation resistance.