HiLetgo VOT-8 Voltmeter Kit Voltage Meter Electronic Production Suite DIY Kit for Student Electronic Exercise Portable Electrical DIY Set A good exercise for students in electronic production VOT-8 voltmeter kit by the key switch control in two-wire system or in the three-wire state work. Two-wire system (measured voltage is VOT-8 power supply), the measurement range of 3.5 to 25. Three-wire system (a set of 3.5 ~ 25V voltage for the VOT-8 power supply), the measurement range of 0 ~ 30V.