USB Digital Voltage Tester Multimeter 3.7-30V 0-4A - An upgraded charger detector, the AT34. The AT34 features a 0.96-inch high-definition IPS color LCD screen, displaying real-time charging status with indicators for voltage, current, capacity, energy, power, equivalent impedance, and temperature at a glance! Widely compatible with fast charging protocols. The AT34 supports QC2.0, QC3.0, APPLE2.4A/2.1A/1A/0.5A, Android DCP, and SAMSUNG charging protocols, keeping you informed about your phone's charging status! Power-off storage function: The AT34 includes 2 groups of power-off storage. When the data group is set to '0', the current capacity and energy are temporarily stored when the device is turned off, flashing to remind you of the latest data upon the next power-on. When the accumulated capacity exceeds 1mAh, the latest data is automatically cleared, and accumulation restarts. When the data group is set to '1', the current capacity and energy are stored when the device is turned off, and the summation continues when the device is turned on again! Equivalent impedance and load power measurement: Clearly understand the load impedance and current discharge power for better insight into load usage, making operation easier and faster.