Benson Leung, a Google engineer working on the company’s Pixel C laptop who recently took to Amazon to identify potentially dangerous USB Type-C cables, is back at it. He’s now warning people about smartphone maker OnePlus’ USB Type-C adapter and charging cable.

“Don’t buy this #USB #TypeC adapter for your Chromebook Pixel or Nexus 6P/5X phone. It uses the wrong identifier resistor,” Leung wrote in a Google+ post yesterday. “Oneplus needs to get the message that their accessories are out of spec…”

The Nexus 5X charges with the Type-C cable, but it does not come with an adapter. (The Nexus 6P does.) As a result, some people who’ve bought the new smartphone have had to go shopping for an adapter. But the small and stylish one that OnePlus sells to go from micro-USB to USB Type-C is simply not a smart option.

But that’s not all. In a comment on his post, Leung noted that OnePlus’ USB Type-C cable “is not spec compliant.” In another comment, he wrote, “I don’t recommend anyone with a Nexus use it.”

It’s possible that some companies selling these types of accessories could be brought up to spec in the future.

“None of the ones presently available are spec compliant, but several vendors have been in touch with me to repair their broken cables and adapters,” Leung told one Google+ user in response to a comment on his post. “Stay tuned. I will make a post when the first one is available.”