The Z-Neutrino Biological Inversion Catalyser was a device created by the Meta-Crisis Tenth Doctor shortly after his 'birth' in order to destroy Davros and his Daleks to stop them destroying everything when he realised what they were planning to do.
The Catalyser was created from pieces of the Doctor's TARDIS and designed to lock the transmission of the reality bomb onto Davros to kill him and the Dalek army he had grown from his own cells. The transmission would filter around the Daleks, destroying them, and Davros.
The Doctor's double arrived on the Crucible, but before he could fire the weapon, he was incapacitated by an energy bolt from Davros' cybernetic hand. Donna also tried to use it, but was also incapacitated by Davros while asking how to fire it. The Inversion Catalyser was then destroyed by a Vault Dalek. (TV: Journey's End)