President Biden announced from the Rose Garden Monday his administration’s formal rule on so-called “ghost guns,” essential DIY weapons without a serial number that have increasingly been linked to violent crime.

The administration has been working on the rule for nearly a year, amid opposition from the gun lobby and 2nd Amendment activists, as well as pressure to slow the recent surge in violent crime in the U.S.

From the Rose Garden, the president displayed a ghost gun kit and said, “If you buy a couch you have to assemble, it’s still a couch. If you order a package like this one over here that includes that parts that you need and directs the assembly of a functioning firearm, you bought a gun.”