Derringer

Derringers are two-shot break-action pistols, and they are bought for one reason: they conceal in places nothing else does. A flat two-barrel gun disappears in a pocket or a boot in a way that even the smallest semi-automatic cannot.

The trade-offs are severe and worth being honest about. Two rounds, no fast reload, a heavy trigger, minimal sights, and recoil that is genuinely punishing in the larger chamberings because there is so little gun to absorb it. As a primary defensive firearm a derringer asks a lot of the shooter. As a backup that is actually on your person, it has a real place.