1.Solid state design is safer than solenoid testers.2.Low impedance to reduce false readings.3.Indicates voltage without battery.4.Voltage indicated by lights, vibration and tone.5.With continuity beeper and bright work light. 1.固态设计，比电磁测试仪安全。2.低阻抗，以减少错误的读数。3.指示，不带电池的电压。4.电压表示灯，振动和音。5.连续性蜂鸣器和明亮的工作灯。