Open box from an authorized dealer?
it was "Amazon renewed", which are basically open box deals (e.g. returns etc). those have 90 day return, and it's been just over 90 days so no recourse... not really an aurhotized deal in the world of Sennheriser warranty coverage (they only cover regular first sales). The headphone (serial number and condition) are brand new. well 3-4 months new.