Feel free to breathe a sigh of relief, iPhone users. The FBI may have been successful in hacking one of the San Bernardino shooters' iPhones, but apparently that miraculous hack is severely limited in use and the iPhone 6s remains impenetrable for the time being.

As a matter of fact, it appears the iPhone 5c is the only phone vulnerable to the hack, and all variants of the iPhone 6 and iPhone 5s models are safe from the hack.

This revelation comes as a result of testimony from FBI Director James Comey who told reporters that the agency had purchased a tool from a third party to unlock the San Bernardino iPhone. During that time, he stated the tool only worked on a "narrow slice of phones" that does not include the newest Apple models, or the 5s. 

Comey's statement can be taken to mean that the FBI is only capable of hacking 32-bit devices, which in Apple's case means the iPhone 5c. As you may recall, starting with the iPhone 5s, Apple included a 64-bit chip in the iPhone, which is harder to crack.

The team of experts responsible for the tool has yet to be revealed, but Comey said he trusts it, saying that its motivations align with the FBI's.

"The people we bought this from, I know a fair amount about them, and I have a high degree of confidence that they are very good at protecting it, and their motivations align with ours," he said.

That's about as much as we're getting from Comey or the FBI about the hack, though a few select senators are allegedly privy to further information. Sen. Diane Feinstein (D-Calif.) has already been briefed about the method used, while Sen. Richard Burr (R-N.C.) is poised to learn the same info in the immediate future. Why them, you ask? Both are working on a new bill that seeks to limit the use of encryption in technology.

Even if the FBI is incapable of hacking into any iPhone above a 5c, the ability to hack into one at all is victory enough. The agency has already notified other U.S. law enforcement agencies that it will try to help unlock other iPhones from various criminal investigations.

Of course, this limitation hasn't deterred the FBI from gaining access to all iPhones in the future, as evidenced by the fact that it has yet to inform Apple about the method used to perform the hack.

"We tell Apple, then they're going to fix it, then we're back where we started from," Comey said. "We may end up there, we just haven't decided yet."

So yes, the FBI can't hack into anything above a 5c, but that isn't due to a lack of trying. Furthermore, the agency's ability to do so doesn't resolve the issue that has been at the center of the debate from the beginning: whether Apple should be required to grant the government access to customers' personal information.