Diamondback Firearms SDR, Self Defense Revolver, DA/SA, 357 Magnum/38 Special, 3 Barrel, Stainless Steel Construction, Polished Finish, Silver, Black Rubber Grip, Fiber Optic Sights, 6 Rounds DB0700S703 The SDR (Self Defense Revolver) is your ultimate ally in self defense, combining reliability, concealability, and confidence into one powerful and compact package. Boasting an exceptionally smooth trigger pull, low profile front and rear fiber optic sights, and a six shot capacity, the SDR makes the perfect companion in any situation.