I also have them on Stamp N Store's 6x7 magnetic sheets which actually measures 6 x 6 3/4 inches.
I created my own clear pockets to house my Framelit and Die Sets. Which are specifically designed to fit the 6x7 magnetic cards. To create these clear pockets, I used laminate pockets by Scotch 5mils, and clear sheet protectors.
Scotch Laminating Machine
You will need a trimmer and a 2" circle punch
Enjoy the 7 minute video below on how I created the clear pockets to store my Dies. Share in the comments below on how you store your Die Sets.