Ruger LCP
The Ruger LCP, a .380 pistol, is 5.16 inches long, 3.6 inches high and 0.82 inch wide. The drawbacks of this model are its availability in only one caliber and its limitation to a capacity of seven rounds (six in the magazine and one chambered).
Glock Subcompact
The smallest Glock handguns are found in its subcompact line. These pistols are 6.29 inches long, 4.17 inches high and 1.18 inches wide. They are available in multiple calibers and have higher capacities, starting at 10 rounds.
Concealable
The size of the Ruger LCP makes it easily concealable in your pants pocket or with an ankle holster. The Glock subcompact is also very concealable, but to a lesser degree; its size is a bit large for an ankle holster or a pants pocket.