Unfortunately there is no hard and fast set of criteria to help identify a counterfeit product. The skills of the counterfeiters can often make it hard to visually distinguish a counterfeit from the original product.
With that said, reliable warning signs include products being offered at an extraordinarily low price and products being offered by persons other than Sennheiser's authorized distributors.
Particularly when buying on the Internet we suggest looking closely at the above mentioned criteria that would point to a fake product offering. Many products on online-auction platforms are counterfeits so you cannot be sure that Sennheiser products being advertised as "new" are not counterfeits. If the price offered is very low ensure that this Internet Dealer is listed as an authorized dealer on our dealer locator on our website.