If you don’t want to lose your spare lithium batteries for your camera, notebook or cell phone, you might want to pack carefully for your next flight.

New rules from the Transportation and Security Administration that take effect on January 1 ban travelers from carrying loose lithium batteries in checked baggage. Passengers are allowed to pack two spare batteries in their carry-on bag, as long as they’re in clear plastic baggies.

Fortunately, you don’t have to worry about the batteries that are already installed in the devices you’re bringing. The TSA has said it’s safe to check in items like a laptop or iPhone that already have the batteries in place.

The agency said that loose lithium batteries not installed in devices pose a fire risk to passenger planes. Recently, the National Transportation Safety Board could not rule out the possibility that lithium batteries started a fire in a plane at the Philadelphia National Airport last year, according to the Associated Press.