Powerful compact units measure impedance at 100Hz, 330Hz, 1KHz and 10KHz, providing accurate measurement of a single loudspeaker, an entire distributed system, or individual components such as resistors, capacitors and inductors. 31/2 digit LCD display clearly shows system impedance with accuracy of up to 0.1O. On 70V distributed systems, it calculates the wattage rating of the entire system. Measurements are taken at audio frequencies, which allows use with impedance matching transformers, switchers and volume controls, providing more accurate readings than with conventional DMMs.