What is the validity of the visitor visa sponsership papers?

[hshah]

Hi,
I would like to know , what is the validity of the visitor visa sponsership papers.
I had sent the papers dated Nov.2007 and the visa date is March 2008
So, the papers would be around 5 moths old.
Does any one knows what is the validity of the papers? Is it 6 motnsh or 90 days ?

Thanks for the help.

[usadesi]

6 months good to go.