Donald Trump is wanting to make changes to a decades-old gun law that dates back to the Prohibition-era. The 1935 National Firearms Act (NFA) restricted the sale and use of gun suppressors, also called silencers.

Under current law, buyers must be over 21 to purchase from a dealer, or 18 from an individual. They must pass a background check, pay a $200 fee, and live in one of 42 states where suppressors are legal. States like California, New York, and Hawaii have banned them.

Suppressors protect hearing, reduce recoil, and improve accuracy. The American Suppressor Association (ASA) says they “are not silent… They are simply mufflers for firearms.” Gun advocates argue they make hunting more humane.

Earlier this month, Trump signed an executive order asking Attorney General Pam Bondi to review gun laws. The order aims to “end the federal government’s violation of Americans’ fundamental Second Amendment right.”

Knox Williams, ASA’s president, praised Trump’s move: “We’d like to thank President Trump for his fearless leadership.” If Trump’s changes succeed, buying a suppressor would require only ID and a quick background check, replacing the current process, which can take “anywhere between one to 100 days,” according to SilencerShop.