A £100,000 budget for the construction of Turing's machine was acquired and the contract to build the bombes was awarded to the British Tabulating Machine Company (BTM) at Letchworth. BTM placed the project under the direction of Harold 'Doc' Keen. Each machine was about wide, tall, deep and weighed about a ton. On the front of each bombe were 108 places where drums could be mounted. The drums were in three groups of 12 triplets. Each triplet, arranged vertically, corresponded to the three rotors of an Enigma scrambler. The bombe drums' input and output contacts went to cable connectors, allowing the bombe to be wired up according to the menu. The 'fast' drum rotated at a speed of 50.4 rpm in the first models and 120 rpm in later ones, when the time to set up and run through all 17,576 possible positions for one rotor order was about 20 minutes.