The actual sound of the FA-003 is very open and sounds like an open headphone design. However, the isolation is very good. It has a very balanced, neutral sound without ever being sibilant or boomy. The treble is smooth and moderately extended without being bright or sibilant. The bass is extended but very tight and controlled. In overall, they are light, comfy and sound fantastic.
Source: http://www.head-fi.org/products/fischer-audio-fa-003/reviews
Frequency range: 10-26500 Hz
Sensitivity: 105 dB
Impedance: 64 Ohm
Input power: 120 mW
Set: additional cuhions, 6.3mm jack adapter
$165.00