I use duel decks to teach people Magic: The Gathering. I like to keep these decks together as they are balanced against eachother for fun matches. So here's a deckbox that does exactly that.

• No parts required, fully printed
• Fits 2 decks of both 60 single-sleeved cards

If you want any adjustments, let me know in the comments. I will upload modifications as soon as possible.