1. Use high quality materials, durable 2. Compact size and exquisite appearance 3. Easy to use 4. High efficiency, reliable and stable performance 5. Wide range of applications Active current output: 0-22mA (minimum output is about 0.1mA), load 0-550Ω Passive current output: 0-22mA (minimum output is about 0.1mA), external power supply 15V-30V, load 0-550Ω Voltage output: 0V-12V (minimum output is about 0.05V) 24V output voltage: Drive current 35mA, do not use more than 35mA Battery undervoltage prompt. When the undervoltage indicator lights up, please shut down and charge it in time If you do not use it a long time, charge it at least once every 2 months to prevent battery damage MICRO-USB interface power supply or charging Use ring mirror: 0°C-50 °C without condensation Due to different factory batches, the product words are different, and the product accessories have slight differences in color and appearance, but it does not affect normal use Colour: Material:Circuit board + plastic Package Contents: 1 x 4-20mA signal generator Only 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.