The Doctor's recorder

A recorder is a musical instrument used by blowing down a slit at the top and putting your fingers (and thumb) on the airholes to create a sound.

The Second Doctor owns a recorder and often likes to play. He uses it mainly as a way of soothing himself while he attempts to think of ways to get out of tight places and to conjour up new plans but also a sorce of self amusment.

The recorder plays a somewhat major part when all three Doctors encounter Omega. It is used somewhat accidentaly in the TARDIS' Forcefeild and is later used in a portable forcefeild that Omega knocks forciing it to explode killing the renegade Time Lord.

The Fifth Doctor also tries to play the recorder but realises its just not him.