Torchwood stun gun
From Tardis Wiki, the free Doctor Who reference
Torchwood stun guns have two settings, one for killing and one to stunning. It works by "shocking" targets who have contact with the muzzle in a similar manner to a taser.
Gwen Cooper used one of these guns against her boyfriend Rhys, so that she could take him to the Hub without having to convince him to do it. (TW: End of Days)
It could be Ianto Jones favourite as when Jack Harkness said this is for Ianto when stuning someone. (TW: They Keep Killing Suzie) he was seen useing one. (TW: Reset)
