Mini Clamp Meter -- ACA, ACV, DCV, Ohm, Diode, Buzzer. The GCM-403 is digital clamp meter can measure AC/DC voltage, AC/DC current, resistance, diodes, continuity, capacitance, frequency and temperature. Tapered jaws, auto range, data hold, REL function and auto power off which makes it a superb tool for electricians. The GCM-407 is digital clamp meter with true RMS measurement. Featuring tapered jaws, a wide range (AC 600A/750V, DC 1000V max input), capacitance measurement as well as non-contact voltage sensing function and the ability to keep MAX/MIN or hold data and automatically power down make the GCM-407 suitable for almost any cable measurement task. NEW OLD Description GCM-403 GCM-302 Compared with the old model- AdvantagesGCM-403 expanded measurement items: DCA/Capacitance/Temperature/Frequency Counter and expanded functionalities: REL, Data HoldCompared with the old model- DisadvantagesSmaller GCM-403 Clamp which is only ∮ 28mmGCM-403 does not have Max Hold GCM-407 GCM-303 Compared with the old model- AdvantagesGCM-407expanded measurement items: Voltage Range/Capacitance and expanded functionalities : No Contact Voltage (AC only)/ Min Hold/REL/Backlight