A
New, Never open, Never used.
AB
Like new, just sign of wear.
B
Few sign of use by terms, or good used condition.
BC
Many sign of use, few small scratches or dents.
C
Heavy useed, noticeable scratches or dents.
D
Defective, missing parts, for study.
Grading of condition is to represent the appearance. Other necessary things are describe.