microphone question

[GuavaHalf]

Often when you see a video of a singer in a studio there is a thin, round object in front of the microphone. What is is and what does it do?

[DrWu]

I think it's just a guard to stop the singer making contact with or getting too close to the mic and unwanted noises turning up on the recording or the sound quality being ruined by too close contact.

[Hammer]

It stops breaths and airflow sounding too loud, particularly the letter 'p'

[mr gary]

it's called a pop guard or pop shield. when you talk or sing into a mic you expel air towards the mic and as the previous writer says about the letter P, some letters or words have more emphasis. The shield stops you recrding a 'POP' during the session. if you need to use one, you can make one by shaping a metal coat hanger into a circle and then use a NEW! stocking or pair of tights as the shield.

[bluedolphin]

I always thought it was a spit guard and was used as a courtesy  to other users of the mike.....but the above answers sound very much better...