The registrars of stress XL423, XL424, record the values of voltage signal in the necessary period. Instruments are intended for the measurement and the writing into the memory of the values of the signals of alternating voltage to 600 [V]. [Registriruyut]s the value of signal and preserve them before the internal storage of registrar for the subsequent transmission of data on PK. Registrars have the built-in verifying wires with the clamps. Model XL423 is intended for the single-phase networks model XL424 it is intended for the three-phase networks obtaining the accurate results of measurements because of the function Of trueRMS. Possibility of the record of the values of signal during the long time to 6 months. Connection for the sake of PK (RS-232).