Defabricator

The defabricator was a device from the year 200,100. It was previously used by the Trin-e and Zu-Zana robots on the series upgraded version of "What Not to Wear" from the 21st century. Its original use was to "defabricate" clothing by making it disappear from the wearer. Captain Jack Harkness was able to upgrade the device into a weapon, by using spare parts from the destroyed robots.

The weapon fires a bluish beam of energy that was capable of piercing Dalekanium armour and destroying a Dalek. Its original purpose, however, was to automatically remove clothing. Jack killed a Dalek with this but said that it depleted its power source. (DW: Bad Wolf / The Parting of the Ways)

Jack had somehow managed to have brought this weapon along with him when he transported himself back to the 19th century and used the weapon again when the Earth was stolen by the Daleks. Apparently this time he had replaced the power source with a better one as he was able to use it at least twice: killing a Dalek and the Supreme Dalek. (DW: The Stolen Earth / Journey's End)