A Minneapolis gun shop has just debuted an affordable gun small enough to be easily concealed, making it a potential tactical threat to police officers.

The double-barreled rectangular weapon is about the size of a credit card. It sells for $100 at Koscielski’s Guns and Ammo, owned by Mark Koscielski, who manufactures the gun with partner Patrick Teel.

The new guns don’t count as firearms because they’re muzzleloaders, say Koscielski and Teel. The user has to pour a measured amount of gunpowder into each barrel, manually insert a total of 14 BBs, and tamp in a small wad of paper. Each barrel fires seven standard steel BBs when one of two electric triggers is activated.

While some critics say Koscielski’s claim that the device is “the ultimate self-defense weapon” is laughable, it could cause harm to someone’s eyes and face when used at close range.

Koscielski says the weapons he manufactures and sells are legal, will set off metal detectors, and are easily identifiable.