Images and description copied verbatim from https://gradolabs.com/headphones/prestige-series/item/131-sr325x. Transducer Type: Dynamic Operating Principle: Open Air Frequency Response: 18 - 24,000 hz SPL 1mW: 99.8 dB Nominal Impedance: 38 ohms Driver Matched dB: .05 dB The Sound of Metal...