1. First, make sure that you have registered your KOSS headphones. If you haven't, you can do so by following the steps below:
2. Once your headsets are registered you should securely package up the headsets that need repaired/replaced with a check or money order for $10.00 per headset to cover shipping costs. Send the headsets with your check or money order to:
KOSS Lifetime Limited Warranty
4129 N. Port Washington Avenue
Milwaukee, WI 53212
Links:
[1] http://www.koss.com