Quartet builds upon the exacting engineering utilized in Duet and Duet+ to deliver very precise and repeatable Interferential and Muscle Stimulation therapy across up to four therapy. Quartet adds 8 additional therapies - 2 Russian Muscle Stimulation protocols and 6 Sequential Stimulation protocols. Quartet's Quad Boost electronic circuitry ensures accurate therapeutic output up to the specified maximum of 25V (50 milliAmps/Peak). The sophisticated, up to date digital circuitry including Texas Instruments Ultra Low Power microprocessors, allows Quartet to deliver nearly two hours of 4 channel effective stimulation at repeatable, precise parameters on a single battery charge using the included EAZE NiMH rechargeable batteries. In addition, Quartet features the same safety and convenience features of Duet and Duet+ as highlighted previously.

Federal (U.S.A.) law restricts this device to sale by or on the order of a practitioner licensed by law of the State in which he/she practices to use or order the use of the device.