Fortify VR, Model No. CD1231-40, CD1231-40Q. Fortify ST VR, Model No. CD1241-40, CD1241-40Q. Fortify Assura VR, Model No. CD1257-40, CD1257-40Q, CD1357-40C. Fortify Assura ST VR, Model No. CD1263-40, CD1263-40Q, CD1363-40, CD1363-40Q. Fortify DR, Model No. CD2231-40, CD2231-40Q. Fortify ST DR, Model No. CD2241-40, CD-2241-40Q, CD2263-40, CD2363-40C, CD2363-40Q. Fortify Assura DR, Model No. CD2257-40, CD2257-40Q, CD2357-40C, CD2357-40Q. Fortify and Fortify Assura implantable cardioverter defibrillators (ICDS) are intended to provided ventricular anti-tachycardia pacing and ventricular defibrillation for automated treatment of life threatening ventricular arrhythmias. The devices may also be programmed to provide single or dual chamber bradycardia pacing. Unify and Unify Assura cardiac resynchronization therapy defibrillators (CRTDs) are intended to provide ventricular anti-tachycardia pacing and ventricular defibrillation for automated treatment of life-threatening ventricular arrhythmias. The devices may also be programmed to provide single or dual chamber bradycardia pacing, in additional to cardiac resynchronization therapy via left ventricular pacing