Additional Details ------------------------------ Product description: Block Distracting Outdoor Noise -- For serious treasure hunters and metal detecting enthusiasts, this set of Gray Ghost Headphones is custom designed specifically to pick up on "ghost signals" others are missing. -- Outdoor noise will no longer detract you from a target, as the super sensitive headphones detect the appropriate signals and a special sound-blocking muff design eliminates environmental ambient noise up to 24 decibels. -- An adjustable padded headband offers comfort with soft, full-ear surround cushions. Rugged, tough, and made to stand up to outdoor use, the headphones offer superior durability. Single rotary volume control features "stay put" segmented "click" positioning. -- Unit also includes a selector switch for metal detector compatibility with all single-output metal detectors without adapters. -- Frequency response: 200Ð3200 Hz. -- Sensitivity: 72 dB @ 1kHz min. -- Impedance: 150 ohms nominal. -- Includes a limited lifetime warranty.