I was curious why his mail has a big red #12 stamped on the envelope?

My comes with a BIG RED STATE PRISON on them, I am guessing the same reason they have to remind you on the phones a 1000 times that "this call is from an inmate at a somethin somehtin state prison" Oh and " this call will be montiterd and recorderded" just to make sure EVERYONE know's where they are!

Good question, I don't know the answer. Where Sam is they stamp with red the facility where is is at. Its pretty big too.

Mine does not have at all - my manis at Winslow in Arizona and no-one would ever know it was from a prison facility if it was not for the return address.

mine letters don't have stamps....they have a little note inside the envelope saying :
GENERAL INMATE CORRESPONDENCE-TEXAS DEPARTMENT OF CRIMINAL JUSTICE-INSTITUTIONAL DIVISION
Like I don't know where it's coming from*L*

I don't think mine have a stamp...I will have to look...
IF I get a letter today!!! :D

On his envelope there is a place on the back that lists the facility and then has lines where he has to put his name and number.