California isn't playing around with 3D-printed guns.

As Motherboard reports, Governor Jerry Brown on Friday signed legislation that will now require anyone who 3D prints a gun to obtain a serial number or "other mark of identification," and affix it to the weapon within 10 days. In addition, owners will need to have a background check and no 3D-printed guns can be sold or transferred to another party.

As 3D printing has become a hobby for many across the globe, some have used the technology to print what are effectively plastic guns. While the National Rifle Association (NRA) and other gun rights groups slam 3D-printed gun restrictions, arguing that such measures violate the Second Amendment, some lawmakers argue that they present a public safety concern. Guns could get through metal detectors and be unsafe, for example.

Meanwhile, according to the state legislature, existing law "requires licensed importers and licensed manufacturers to identify each firearm imported or manufactured by using the serial number engraved or cast on the receiver or frame of the weapon." But the law doesn't cover sales of gun parts.

"There are no provisions in existing law that prevent a person from buying an 80 percent lower receiver and then making it into a fully functional firearm," according to a state Senate analysis. "Because 80 percent lower receivers are not considered firearms, a person purchasing them does not have to go through a federal firearms dealer, and does not have to undergo a background check. This bill is intended to close this loophole."

Those who violate the law by making a handgun face up to a year in jail, a $1,000 fine, or both. For all other firearms, the bill calls for up to six months in jail and a $1,000 fine, or both. Each firearm is a considered a separate offense.

According to Motherboard, the legislation requires a stainless steel marker to be placed on the gun so it can be detected by a metal detector. Requiring a background check is a way to keep eyes on who might be creating guns, and the potential quality issues stands at the center of California's decision to eliminate sales and transfers.

The new law goes into effect on July 1, 2018.

This article originally appeared on PCMag.com.