Sonic blaster

A sonic blaster was type of weapon popular by the 51st century. They were produced at the Vilengard factory. They were seen used by Professor River Song and by Captain Jack Harkness, who brought one with him to the year 1941 during his conning days.

The Doctor switched Jack's sonic blaster with a banana at one point. (DW: The Doctor Dances)

Abilities
The blaster used a sonic wave projected into the form of pulsing squares of blue light which could cut through thick walls, and also had a reverse function which could replace the removed chunk of material afterwards. This was deemed a "special feature" of the blaster and it was said to use up a lot of the batteries which it ran on. (DW: The Doctor Dances)


 * Jack explained that the blaster used digital technology, so by implication, the blaster could encode the molecules of the destroyed materials and re-integrate them from the same source.

The blaster has never been seen used as an offensive weapon but as a tool. Although Jack brandished the gun towards the gas masked zombies and explained that the blaster could also function as a sonic disruptor and a sonic cannon, it has only ever been seen as a means of escape or forced entry. Jack used it to open a door by removing the lock and Rose used it to remove a hole in a floor, but notably not her, Jack's or the Doctor's feet. The Doctor and River Song used it to blast away chunks of wall in order to escape the gas mask zombies and Vashta Nerada respectively. (DW: The Doctor Dances, Silence in the Library / Forest of the Dead)

Behind the scenes
Production staff referred to this weapon as the "squareness gun" before the Doctor called it by that name. Furthermore, Steven Moffat has suggested that River's gun might be the same one Jack used, as he apparently left it in the TARDIS when he parted ways with the Doctor. (Doctor Who Confidential) This was confirmed in IDW: Tesseract, but the over time the handle had changed from a dark brown to an ivory colour. (DW: The Doctor Dances, Forest of the Dead)