This is a very fascinating little pistol.  The Doubletap Defense Derringer was inspired by the Liberator 45ACP,  an interesting disposable firearm designed in WW2 that was airdropped by the thousands on top of war worn cities in hopes that endangered civilians would pick them up and use them to obtain a better firearm (it didnt work), but nonetheless created a very interested piece of history. 
 
While the Liberator had one of the most simple designs imaginable for a firearm, the Doubletap Defense Derringer took a different approach, being one of the most over-engineered Derringers ever developed.  It boasts a very impressive level of accuracy for something of its stature, a buttery smooth 1911 style trigger, an impressively concealable form factor, A springloaded ejector switch, and even a storage compartment inside of the grip which is capable of holding additional rounds of 45ACP.  
 
Doubletap Defense has since become bankcrupt, therefore discontinuing all versions of this derringer.  This means, much like the Liberator, the Doubletap Defense Derringer is now part of history.  And you can own it today, brand new in the box, with all included accesories for $465!