Mail

A lot of inmates take a lot of comfort in sending and receiving mail.  The ICJ limits you to receiving post cards -- they claim that it takes too much staff resources to screen letters in envelopes for contraband.  You can receive envelopes with legal papers if your attorney uses envelopes imprinted with their office letterhead.  

When it comes to sending, you can mail out either post cards or letters in envelopes.  Pre-stamped post cards and pre-stamped envelopes are available for purchase from the Commissary.  You'll get very good at writing in very small print to get the most out of each post card.

A special category of mail is between inmates at the jail.  I met a young man who was incarcerated at the same time his girlfriend was.  (Kid, we'll always have Mason.)  Their paths would never cross in jail, unless maybe both were in CATS or AA together.  So they sent each other post cards in the U.S. Mail.  ICJ encourages this practice.  Keep in mind that your fellow inmate can't receive envelopes, so you'll have to use post cards.