DetectorPro Black Widow Headphones for Metal Detecting Dual rotary volume control with "stay put" segmented "click" positioning. Selector switch for metal detector compatibility with all single-output metal detectors without adapters. Frequency response: 200 - 3200 Hz... only what your detector uses. Sensitivity: 72 db @ 1 KHz Min. Speakers designed for maximum volume, sensitivity, efficiency, durability, and signal quality.