So you are looking for a super compact gun for self defense? The LifeCard .22LR has you covered. It is about the size of a credit card when folded. It unfolds to give a full-size handle and has built-in safety features. The handle has space for up to 4 extra rounds.
The gun measures 3.375in x 2.125in when folded. It has a fully machined billet construction.