More than $635,000 in counterfeit Apple adapters and USB cables were seized by U.S. Customs and Border Protection (CBP) during a routine search in Anchorage, the agency announced Thursday.

The goods arrived in Alaska via plane from China, and were heading toward several locations in the continental U.S.

Designed to look like iPhone 5 USB "lightning" connector cables and adapters, the products included fake Apple logos and Underwriters Laboratories (UL) trademark icons.

But the knock-off logos weren't enough of a disguise. The items stood out as counterfeits, Frank Falcon, CBP spokesman said. They were packaged for retail sale in cardboard blister packs that were sub-standard compared to Apple's trademark white packaging.

Falcon said a manufacturer in China is responsible for the shipment. He noted that while it is "difficult to deal with a manufacturer in another country," the bust will "bring more scrutiny" to future shipments from the company.

This is a large bust for such products. As one can imagine, over $600,000 in cables and adaptors means there was "quite a bit of stuff" seized, Falcon said.

Besides copyright infringement and other economic concerns, potential safety hazards from the items pose additional threats. The presence of the UL logo indicates that a product has been evaluated for electrical shock and fire hazard, and unauthorized use of the logo means that improperly labeled items could pose a safety risk to consumers.

It is unclear whether the cables work at all, Falcon said.