Print as many copies as you need and make sure to laminate each for durability. I circle the levels with a Sharpie that are "just right" for each student. Use an Expo marker to erase the Sharpie when you need to change the levels - no need to reprint.
I have students keep this card in their book box. It is a tool to guide them when choosing just right books and also doubles as a bookmark. Students are not required to choose books on their level, but it gives them a places to start.
Levels A-M correspond with K-2 grade Fountas & Pinnell reading levels.