Temperature Control: The audio impedance meter has a temperature control feature to ensure accurate readings. Nonstick Coating: The meter has a nonstick coating that makes it easy to clean. Manual Controller: The meter has a manual controller for precise adjustments. Dishwasher Safe: The meter is not dishwasher safe for easy cleaning. Compact and Portable: The meter is compact and portable for easy use in the field. Active device is essential for reliable installation of background music and paging systems in residences, offices buildings and public areas. Avoid costly service calls and amplifier damage by verifying actual speaker system impedance prior to operation. Unlike conventional volt/ohm meters, which measure DC resistance, this unit utilizes an internal 1KHz oscillator to measure true impedance. Accurately measure speaker lines that utilize impedance matching volume controls, switchers, transformers and passive crossovers Because this unit accurately measures up to 20Kohm, it may also be utilized with 25V, 50V, 70V, and 100V speaker line transformers in commercial installations (information included in the manual) Large digital display features 1" characters for easy viewing Rotary selector provides 200Ω, 2KΩ and 20KΩ scales Rugged, double insulated case is CATIII rated for use up to 200V Dimensions: 3" (H) x 7"(W) 3-1/4"(D) Includes: Test leads, carry case and owners manual Requires six “AA” batteries, not included