1. The working time and capacity display has a memory function after power off.2. Press the RTZ reset button for 3 seconds and the screen display will be reset.3. USB intelligently monitors current and voltage capacity.4. Portability: This product is small in size, light in weight, and very convenient to carry.5. : This product is made of high-quality materials, exquisite workmanship, very and long service life.It can also help safe charging and monitoring your charging data in real time.Model: KWS-V21Voltage: Input/Output Voltage: 4-20V, Voltage Resolution: 0.01VCurrent: Input/Output Current: 0-3A, Current Resolution: 0.01AAmbient temperature: 60 (℃)Accuracy: ±1%Line loss: about 0.1 ohmsColour:transparent blackMaterial:plastic+metalSize:73 x 23 x 13.5mmPackage Contents:1 x USB TesterOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.