From amprobe.com: Amprobe began is life in Long Island, NY in the late 1940's under the name Pyramid Instrument Company. In 1960 the company name was formally changed to Amprobe Instrument Corporation. Amprobe continued to design, engineer, manufacture and distribute product from its Lynbrook, NY location until it was merged to form ATP and relocated to South Florida in late 1999. Among the first products was the Clamp-on Inductive Ammeter, for which the company received its first patent in September 1950. Throughout the 50 plus years since, the Amprobe™ name has become synonymous with clamp-on meters, to the point where it is commonly used as a generic term for such. Nevertheless the brand has expanded its product offering to over 250 items and has become an established leader in quality test equipment for professionals in the electrical, maintenance, construction, and HVAC markets. Among the most innovative and recognized Amprobe products are the RS-3 rotary scale clamp-on, the DM-II Power Recorder, the "AT" and "CT" series of wire and current tracers, the Amptran and Deca-Tran current transformers and the Kwik-I-E non-contact voltage and current meter.