Suppressors are regulated under the National Firearms Act (NFA) of 1934, which falls under the purview of the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). To legally purchase or possess a suppressor you must:
Be at least 21 years of age to purchase a suppressor from a dealer.
Be at least 18 years of age to purchase a suppressor from an individual on a Form 4 to Form 4 transfer (contingent on state laws).
Be at least 18 years of age to possess a suppressor as a beneficiary of a trust or as a member of a corporation (contingent on state laws).
Be a resident of the United States.
Be legally eligible to purchase a firearm.
Pass a BATFE background check with a typical process time of 4 to 9 months.
Pay a one time $200 Transfer Tax.
Reside in one of the 41 states that currently allows civilian ownership of suppressors.