These three categories get lumped together as “impact weapons,” but they sit in very different places legally. Some are restricted or banned outright in several states regardless of intent, and some are close to unrestricted nationwide. Treat this as a starting point for your own research, not a final answer — weapons law varies by state and sometimes by city, and it changes over time.
Metal knuckles: the most restricted of the three
Metal (or “brass”) knuckles are the most heavily regulated item on this list. A number of states — including California, New York, and Massachusetts — prohibit civilian manufacture, sale, or possession of metal knuckles outright, with no self-defense exception, and other states restrict them in narrower ways. This applies whether the item is sold as a standalone product like our Heavy Metal Knuckles or built into a keychain, like the Cat Self-Defense Metal Knuckle Keychain — the knuckle-style grip is what matters to the law, not the packaging. Before you buy anything in this category, check your own state’s weapons statute specifically for “metal knuckles” or “knuckle weapons.”
Batons: legal in many states, banned as “clubs” in others
Expandable and fixed batons are legal to own and carry in a majority of states, but a meaningful number — again including California — classify batons as a prohibited “club” or “bludgeon” for civilians, sometimes with exceptions for licensed security or law enforcement only. A slapjack or sap, like our 8.5″ Leather Slapjack, typically falls under this same “club” category in states that restrict it, even though it looks very different from a baton. If batons are legal where you live, something like the Police Force Tactical 21″ Expandable Steel Baton is a common, straightforward choice — but confirm that legality first, since this is one of the more commonly misunderstood categories.
Kubotans: the least restricted option
A kubotan — a short, blunt keychain rod, sometimes with rounded ridges for grip — is generally treated as an ordinary keychain accessory rather than a weapon in most states, since it has no blade, no spring mechanism, and no edge. Options like the Self Defense Kubotan Key Chain are a practical everyday-carry pick in places where metal knuckles or batons are off the table. One exception worth knowing about: a kubotan built around a concealed blade, like the Kubotan Keychain Hidden Knife, is legally a knife first and a kubotan second — so it’s subject to your state and city’s knife laws (blade length limits, concealment rules, and so on) in addition to anything that applies to kubotans generally.
How to actually check before you buy
Search your state’s penal code or “prohibited weapons” statute for the specific terms “metal knuckles,” “club,” “baton,” “blackjack,” or “slapjack” rather than relying on general impressions — these categories are defined narrowly and inconsistently from state to state. Also check your city or county code, since some localities add restrictions on top of state law even where the state itself allows an item. When a product’s legal status is genuinely unclear where you live, the safer and more broadly legal choice from this list is almost always a plain kubotan.