The IF 4K™ digital interferential offers multiple treatment modes and can last up to 2 hours off ■ Dual Channel Digital Device • Waveform. Syiiuiietiicul Balanced Sine Wave ■ Treatment Timer: Continuous, 15, 30, 45 or 60 ■ Usage Timer: Maximum 999 hours 59 mins ■ Power Source: 4 x 1.5V AA battery Superior Battery Life: off of the AC Adapter this device will last 2 hours. Other IF devices last less than 20 minutes. Very important for that patient who is on the go but still needs IF to make it True Sine Wave technology: This device produces a true sine wave, important to some practitioners who use a let of Interferential waveforms. A sine wave means the waveform is balanced, producing more effective pain relief. Compliance Meter-this device shows how many times the patient has used the device, important for worker's compensation companies. 6 preset IF modes and very easy to use! Looks like a flip cell phone, so more privacy for This device Includes a free AC Adapter!