President Donald Trump is expected to announce that he will be signing a ban on bump stocks that gives Americans 90 days to hand them over or otherwise dispose of them.

Bump stocks were used during the October 1, 2017, Las Vegas attack. That attack marked the first time that bump stocks were known to have been used in a crime.

The ATF circulated language to ban bump stocks at Trump’s direction in December 2017. The public was allowed to comment and gun control outlet The Trace reported that 85 percent of those who commented opposed a ban.

CNN reports that Trump is now preparing to sign the ban and it will outlaw the firearm accessories without a grandfathering option. CNN quotes a source that indicates “members of the public will be given 90 days to turn in or otherwise discard their bump stocks.”

ATF Acting Director Thomas Brandon told the U.S. Senate he anticipates a legal challenge against the ban and acknowledged that that challenge could slow the ban’s implementation.