The PSA grading scale, from PR 1 to GEM-MT 10

The PSA grading scale is the 1-10 scale Professional Sports Authenticator uses to rate a card's condition, from PR 1 (Poor) to GEM-MT 10 (Gem Mint). In full, the grades are 10 GEM-MT, 9 MINT, 8 NM-MT, 7 NM, 6 EX-MT, 5 EX, 4 VG-EX, 3 VG, 2 GOOD, 1.5 FR and 1 PR.

PSA may give a half-point grade between PSA 2 and PSA 9, such as 8.5, but there's no PSA 9.5. A qualifier such as OC (off center) or ST (staining) can be added to a grade for one specific flaw.

Before you buy one

• Don't mix grade words with condition words. A PSA 7 label reads "NM", but a raw card listed as NM is only the seller's opinion. Know which one you're reading. See the condition scale.

• Check for a qualifier. A qualified grade isn't the same as a plain one, so read the label for a qualifier before you compare a slab with others of the same number.

• Search each grade on its own. Titles lead with the number, not the name: "PSA 9", "PSA9", "PSA 8.5", "PSA 8 NM-MT". A half grade is a different grade, so search each one you'd accept separately.

A ChaseBoard PSA 8 watch matches "PSA 8" and "PSA 8.0" in a title, but not "PSA 8.5". One watch can hold several grades, so if you'd take either, put PSA 8 and PSA 8.5 on the same card.