【Professional RCD/Loop Testing】Advanced electrical safety testing instrument designed for residual current device (RCD) and loop impedance testing in residential, commercial, and industrial applications. 【Multi-Function Measurement】Comprehensive testing capabilities including trip current, trip time, contact voltage, loop resistance, frequency measurement, and voltage testing (0-440V AC). 【Large Data Storage Capacity】Store up to 1000 measurement results with easy access through MEMO function and USB 2.0 interface for PC data transfer and analysis. 【High-Resolution LCD Display】4.7 inch backlit LCD screen with clear digital readouts, automatic range selection, and safety warning indicators for enhanced visibility in all lighting conditions. 【Multiple Test Modes】Supports various test configurations including L-N, L-PE, N-PE connections with selectable test currents (10mA, 30mA, 100mA, 300mA, 500mA) and fast/slow testing modes. 【Safety Compliance】Meets EN61010-1, EN61557-3, EN61326-1 standards with CAT III 1000V and CAT IV 600V safety ratings for professional electrical testing applications. 【Portable Design】Compact dimensions (188 x 145 x 73 mm) with protective rubber housing and carrying case for convenient field use and transportation. Specifications: Model: HT5910 Display: High-resolution backlit LCD Dimensions: 188 x 145 x 73 mm Weight: Approximately 708g Power Supply: 8 x 1.5V AA batteries (not included) Voltage Measurement Range: 0-440V AC Frequency Range: 45-65 Hz Loop Resistance Range: 0.1-2000 Ω Test Current Options: 0.5, 1, 5 times rated current Current Settings: 10mA, 30mA, 100mA, 300mA, 500mA Data Storage: 1000 measurement records Safety Rating: CAT III 1000V, CAT IV 600V Operating Temperature: 0-40°C Storage Temperature: -20 to 70°C Auto Power Off: 10 minutes Interface: USB 2.0 Material: ABS plastic with rubber protection