Highlights of legislation that received final congressional approval on Monday from the Senate prohibiting undetectable plastic firearms.
—What the bill does: Extends for 10 more years the ban against guns that are not visible by the type of metal detectors or X-ray machines used at airports.
—Why it is needed: Supporters say undetectable firearms are a growing threat because the proliferation of and improvements to 3-D printers means plastic guns will become increasingly available.
—What would have happened without congressional action: The law, first enacted in 1988, would have expired Tuesday morning.
—What Democrats wanted: A requirement for a permanent metal part. Some plastic guns today have detachable metal pieces that technically obey the law but leave such weapons hard for screeners to detect.
—How President Barack Obama, in Africa, will sign it: He will order the use of an autopen, which can replicate his signature. Under President George W. Bush, the White House ruled the use of such a device is legal.