USB Load Tester, DROK DC 3-21V Load Battery Tester, 35W 3A Portable USB Monitor, Intelligent Constant Current Electric Discharge Resistance Power Resistor Kit NOT ONLY A LOAD, BUT ALSO A MULTIMETER: DROK load tester can continuously discharge at 35W for a long time. Besides, it is also a USB multimeter which can be used to real-time monitor the voltage, current, capacitance, electric energy, power, temperature, conductive time for smart phones, power banks, and USB charger/wall USB charger when they are discharging and aging. DUAL ADJUSTMENT DESIGN: The battery monitor tolerates the widest voltage range (DC3-21V) and current range (0-3A). Our USB detector owns dual adjustment design (current coarse adjustment 0.1A & current trimming 0.01A) and intelligent temperature control, which can help you get more accurate testing result. INTELLIGENT TEMPERATURE CONTROL: Our resistor set is equipped with large fan and high quality aluminum radiator, strong heat dissipating. Furthermore, the load resistor has intelligent temperature control, which can effective product the module from damaging. MULTIPLE USB PORT: The feature-rich battery tester load has various USB ports (Mini USB data cable port, USB Type-C for reversed USB connection, Android data cable port, Single wiring terminal or aluminum battery power supply testing port). Suitable for detecting the quality of different USB chargers. Note: Apple iphone data cable port is not suitable. EFFORTLESS OPERATION &INSTALLATION: One button achieve clearing or resetting data. You just need to plug the electronic load to the power bank, smart phone, chargers or other device which you need to discharge,(not suitable for iPhone and its charging cable) no need wiring, screws or other tools, super easy and simple installation.