technical characteristics: Work voltage: 3V-6V； DC impedance: 450Ω?0Ω/20癈； Applicable pulse width: 50ms-600ms； Applicable frequency: ≤4HZ Deferent moment: 57礜m/4.5V Work temperature -35癈-+70癈 Use life pulse exceed a hundred million times (more ten years) Antimagnetic capability: Accord GB/T17215 standard request Other technical condition: Accord JB5459-91 standard request Applicable ammeter constant: 800/1600/3200imp/kwh