Frequency response: 20-20,000 Hz
Impedance: 32 ohms
Sensitivity: 100 dB SPL
Sound: Active Noise Reduction (ANR) headphone system reduces harmful and annoying low frequency sounds in noisy environments
Volume: In-line volume control
Cord: Unplugs for wire-free passive and active noise cancellation
Structure: Fully collapsible
Structure: Extra-soft, padded headband
Headphones with closed leatherette ear cushion for added passive noise reduction
Straight, single entry 4 foot cord
Limited Lifetime Warranty
QZ900 headphones are the latest addition to the Koss Quiet Zone line and add a new level of noise reduction, performance, and comfort. The electronics package inside each ear cup is designed to monitor outside noise received through specifically mounted microphones in each ear cup.
Once this incoming noise can be analyzed, the Koss QZ900 circuit introduces a sound wave that is 180 degrees out of phase with the incoming signal. The result is what Koss engineers term "zero earth" at the point of the eardrum. Most low frequency distractions from airplanes, lawn mowers, fans or even office hum will be dramatically reduced by these noise canceling headphones.
Koss QZ900 noise cancelling headphones will create less reason to turn up volume and overdrive the tiny amplifier in your portable electronics. This means greater efficiency, less distortion, deep rich lows, and sparkling highs.
Unlike most other noise cancelling headphones, QZ900s play music with or without the active noise cancelling circuit engaged. A handy removable cord features an in-line volume control, and one standard AAA battery provides approximately 50 hours of active noise cancellation.
Koss Limited Lifetime Warranty
Each Koss product has a Limited Lifetime Warranty, which covers normal use by the initial user or purchaser of this particular Koss product. Koss hereby warrants only to the initial user or purchaser that this Koss product will be free of any defect in materials and workmanship for the life of the product.
This warranty does not apply to any INITIAL USER OR purchaser who allows this product to be used by multiple PERSONS. This warranty is the sole and exclusive warranty for this Koss product and is in lieu of all other warranties (express or implied), including any warranty of merchantability or fitness for a particular purpose.
The sole and exclusive remedies available to the initial user OR PURCHASER for any defects in materials or workmanship shall be the obligation of Koss, at its sole option, to either refund the purchase price of the Koss product, or repair or replace the non-functioning or defective Koss product provided it is returned to Koss in secure packaging together with a check for $9.00 ($10.00 Canadian) to our factory at 4129 N. Port Washington Ave, Milwaukee, WI 53212.
If purchased outside the U.S. contact the local Koss Authorized Dealer for details.
Koss reserves the right to replace any discontinued product with one of equal value. Koss shall not be liable for any loss, injury or damages to persons or property resulting from the use of this product or any failure of or defect in this product, nor shall Koss be liable to the initial user of this product or to any other person or entity for any general, special, direct, indirect, incidental, consequential, exemplary, punitive, or OTHER DAMAGES of any kind or nature whatsoever. The repair or replacement of any non-functioning or defective product or the refund of the purchase price, at Koss' option, shall constitute Koss' only liability to the initial user or purchaser, whether such liability is based on contract, tort, strict liability or otherwise. Some states may not allow the exclusion or limitation of damages set forth herein in which case the above language may not apply to you. This limited warranty gives you specific legal rights and you may also have other rights, which may vary among states or provinces. If usage of this Koss product violates the guidelines of this limited warranty, Koss will repair the product and charge the purchaser for the cost of company time and materials.