From the back of the book:
Do you have trouble keeping track of your dwarf's hit points? Are you constantly checking to see what your thief's abilities are? Did your magic-user miss going up a level because you lost the piece of paper with all of his treasure on it? Well cast your gaze on this item. At last, all that valuable information has been put on one sheet of paper.
These convenient record sheets display all of the most frequently used information that a player looks for when adventuring with a character. Everything you want to keep track of can be kept on these sheets. Ability scores, armor class, hit points, weapons, spells, treasure, equipment, magical items, saving throws, special abilities and even a combat table are placed at your fingertips.
This is not the same item as either AC6 or REF2, even though it is also a pack of character sheets. AC5 had a limited distribution (two print runs) before the sheets were updated and re-released as AC6.
Confusingly though, this item has exactly the same product code as AC6. It does at least have a different cover image.