Polarity Tester Novel, smart and beautiful appearance Features: Polarity Tester1.Novel, smart and beautiful appearance.2.Use pulse testing, fit for speakers in any type, size, material, and impedance, 3.polarity for earphone and speaker sensor.4.Judge fast auto voice and light, especially fit for production line.Specifications:1.Pulse Width: 0.4ms±0.2ms2.Pulse range: >10Vp-p(output amplitude H)3. ...