Power Supply: external -USB-5V or external power DC 15-30V, each way makes the generator work, both ways also can be connected at the same time. Voltage Output: 0-10V, precision is 0.01V, rotate the encoder knob to adjust output voltage, can be calibrated. Current Output: 0-22mA, precision is 0.01mA, rotate the encoder knob to adjust output current, can be calibrated. Multiple Display: just the small botton to switch the display mode between voltage and current, you can also the instructions to switch 0- or 0-50HZ display. Product Dimension: 3.94inch x 2.36inch x 0.98inch (100mm x 60mm x 25mm), portable and convenient. Note: optional 803040 battery expansibility (battery not included). signal generator is designed to 0-10V voltage signal and 0/4-20mA current signal for PLC and panel Debugging, Device Testing, Frequency Converter, Flow Valve, . easy to use, it can be connected with -USB-5V power supply or DC 15-30V external power. What's more, it can display 4 different types of digit, 0-10V voltage, 0-22mA current, 0- and 0-50HZ. It will play a important role in your electronics work. Colour:Black Material:plastic Package Contents: 1 * Signal Generator(without batter) Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real . The measurement allowed is +/- 1-3cm.