Tyvek Himber Envelopes are great utility poker card size, double sided Himber envelopes, brown color, made in very durable tyvek material.

They are made for switching and multiple outs:

• Switch any freely chosen card into your force card
• Use any two force cards and reveal either one as your prediction
• Use two double face cards in one envelope to have four possible outcomes
• Use any blank card with any words, symbols and numbers for the above applications

I use two of them in my magnetic Himber wallet and there are four outs but spectator sees one envelope and one card.

Comes with 10 tyvek envelopes. No instructions included.