A counterfeit, fake or knockoff item is an illegal copy of a brand name item that attempts to pass itself off as the original. Counterfeits unlawfully replicate trademarked terms and logos. The penalties for importing and/or reselling counterfeit items are severe, and can involve large fines and even a prison sentence. Customs has the right to detain and destroy any goods they suspect to be counterfeit.
In order to avoid buying counterfeits, fakes and replicas you should ask the supplier for a letter from the brand owner which verifies them as an authorised reseller.