The main envelope should be 100 pound cover weight paper.  If you know how thick the invitation is that will go into the envelope, we can create the perfect fit.

The flap of this envelope should match the main envelope.  This envelope should be 100 pound cover weight paper.

We make liners from 80 or 100 pound cover weight paper.  This will make the envelope feel better.  If you want a wall to wall liner, we will duplex before converting the envelopes.

Duplex is to seamlessly glue 2 or more sheets of paper together.  We have duplex invitations up to 1/4 of an inch thick.

Boxes need to be double thick cover weight paper. Add a liner and the box will feel rigid, just like a box should feel.

The envelope is your first impression.  Go cheap and they will understand.