Digital Interference Suppression AC Wall Outlet or Battery Powered Two Direct Connection Frequencies (2 kHz, 33 kHz) Wireless Inductive Antenna or Clamp Modes Passive 50/60Hz AC Tracking Selectable Null or Peak Tracking Modes Selectable Solid or Beeping Tracking Tone Non-contact Inductive Clamp and Inductive Antenna Included. Audible (Speaker or Stereo Headset) or Visual Bar Graph Low Battery Digital Bar Graph Auto Off