Milian Acoustics SV Professional Noise Isolation Headphones 30 decibels of Circumaural Noise Reduction 40 mm Neodymium Drivers - Frequency Response: 20-20000 Hz Impedance: 64 Ohms - Sensitivity: 105 db SPL @ 1 kHz Gold Plated 3.5mm plug plus 1/4" adapter included. Sealed Bass Reflex Acoustic Speaker Chamber