The Bombe machine was developed to speed up the breaking of Enigma, so that messages were still operationally relevant.
The Bombe helped to deduce the day's Enigma settings, of both the rotors and the plug board, by eliminating the many incorrect possibilities.
The Codebreakers created a menu for the wiring at the back of the Bombe based on a hypothesis, known as a 'crib', of part of the original message. Cribs were often derived from regular appearances in decyphered messages of stock phrases, such as 'message number' or 'nothing significant to report'.
The machine was developed by Alan Turing and the case back of the Bremont Codebreaker has been designed to replicate a drum of the Bombe machine.