Apple recently sued US-based firm Mobile Star LLC for trademark infringement, alleging that it has been selling counterfeit goods using Apple logos and product images in its Amazon listings. While the company is looking to protect its brand name, it also argues that buying one of these fakes means you could be putting yourself at risk of fire and even “deadly” electric shock. They are often poorly built with inferior or missing parts, flawed designs, and inadequate electrical insulation.

The Chartered Trading Standards Institute, a UK consumer protection organization, recently recently ran its own tests as part of an investigation into the safety of counterfeit Apple chargers. The result? Out of 400 units all but three “failed a basic safety test,” in which high voltages were applied to the chargers to see if they had enough isolation to protect against electric shocks.

The tests tests were performed by safety specialists UL and the chargers were bought online from eight different countries, including the US, China and Australia.

Leon Livermore, the chief executive of Chartered Trading Standards Institute, urged shoppers to buy electrical goods only from trusted suppliers. “It might cost a few pounds more, but counterfeit and second-hand goods are an unknown entity that could cost you your home or even your life.”

Indeed, paying $30 for a phone charger is ridiculous, but buying a poor quality counterfeit can damage your devices and put yourself at risk. This has become an increasingly troublesome issue for Amazon and is one of the reasons the company is finally cracking down on fake products.

It should be noted that it’s “counterfeit” and not all “third-party” cables and chargers that are considered dangerous. Brands like Amazon Basics, Anker, Monoprice and a few others have been producing quality UL-certified cables and chargers for a fraction of the cost of their original Apple counterparts.