Quantity: One set DC voltage: 600V 1.0%: AC voltage: 450V 1.2%: AC current: 20-400A 2.0% Resistance: 200K1.0% special function 3 1/2 LCD display, maximum reading 1999 Low battery indicator function Overload protection Data hold for easier reading Buzzer on-off and diode test function Battery: 2 AA (AAA) batteries (battery not included) Jaw diameter: 21.3mm Body color: yellow Body weight: about 200g Body size: 150 60 28mm Standard accessories: test lead, manual, warranty card The current clamp meter is called a current clamp meter. Its active part is mainly composed of an electromagnetic ammeter and a through-current transformer. The core of the through-hole current transformer is made into a movable opening and is clamped, hence the name clamp ammeter. It is a portable instrument that can directly measure the alternating current of the circuit without disconnecting the circuit. It is very convenient to use in electrical maintenance and is widely used. The clamp meter is an instrument that integrates a current transformer and an ammeter. It is an important branch of the digital multimeter. Its working principle is the same as that of the current transformer for measuring current. The clamp meter is composed of a current transformer and an ammeter. The iron core of the current transformer can be opened when the wrench is tightened; the wire through which the measured current passes can pass through the opening of the iron core without cutting it, and the iron core is closed when the wrench is released. The wire of the circuit under test passing through the iron core becomes the primary coil of the current transformer, in which the current is induced in the secondary coil by passing the current. For the ammeter connected to the secondary coil to have an indication-----measure the current of the line under test. The clamp meter was originally used to measure AC current, but now the multimeter has all the functions it has, which can measure AC and DC voltage, current, capacitance, diode, triode, resistance, temperature, frequency, etc.Good quality product