True Fidelity (NC300w) are made by the award-winning company AblePLanet. It features their patented Linx Audio technology as well active noise cancellation.Their specs are:Frequency Response: 20 Hz-20 kHz Sensitivity at 1 kHz: 115 db (off); 121 db (on)plug: 3.5 mm (with 1/4" home stereo adapter & airplane adapter)