Callisto Pulse

The Callisto Pulse was a device that could disarm micro-explosives from within up to 20 feet.

It later ended up in the possession of River Song. She offered the pulse to Dorium in exchange for the vortex manipulator she required to reach the Tenth Doctor. It was required by Dorium to disarm the micro-explosives that he had drunk from his glass of wine. The Pulse was in the form of River's earring. (DW: The Pandorica Opens)

Behind the scenes
According to The Brilliant Book 2012, a book that contains non-narrative based information; it was stolen by the Corsair from the Callistan Klepocracy, on a mission for the Celestial Intervention Agency.