(U.S. Customs and Border Protection)

If you find a pair of those trendy red-bottom heels for a deal that sounds too good to be true, it probably is.

U.S. Customs and Border Protection confiscated 20,457 pairs of counterfeit Christian Louboutin shoes at the Los Angeles/Long Beach seaport.

"They label the shipments as generic shoes when, in fact, they're bringing over contraband," said Jaime Ruiz, a public affairs specialist for the U.S. Department of Homeland Security.

According to the CBP, the knock-off shoes that were transported in five different shipments on a cargo ship in large boxes from China had a domestic value of more than $57,000, meaning it cost just less than $3 per pair to make them.

Officials said there were enough of those red soles to add up to a suggested retail value of $18 million, an unbelievable profit.

"The original [Christian Louboutin] shoe is made in Italy," said chief CBP officer Guillermina Escobar. "Once we saw it was coming in from China, we knew there was a problem with the shipment."

Officials took pictures of the shoes and consulted with the trademark holder to authenticate the shoe. Once they learned they were counterfeit, the hot commodities were taken off the black market and placed into the border patrol's possession.

Had the shoes slipped through the cracks, Escobar said, they would likely have been sold on illegitimate websites and underground outlets, some of which may fail to mention the shoes are counterfeits.

The CBP said it will destroy the more than 20,000 pairs of high-fashion shoes, likely by burning them.

Escobar said a total of three different importers shipped the counterfeits on July 27 and Aug. 14 of this year.

The incident is still under investigation but the importers will likely be charged with a trademark violation.

CBP officials said there were 24,792 seizures of counterfeit and pirated goods in the 2011 fiscal year.

One thousand twenty of those trade seizures had a domestic value exceeding $37 million and all took place in the greater Los Angeles area.

"This represents an 18 percent increase in the number of seizures from fiscal year 2010," said Escobar.

The CBP said it knows what hot commodities are coming in to the United States and will make sure to keep an eye out for any more counterfeits.