How to classify pen nib models?

EF: extra fine.

XF: extra fine, same as above, extra fine, this logo is loved by Parker.

F: fine, fine.

M: medium.

B: broad, thick.

L: large, same as above, thick, this logo is what Weidiwen likes to use.

BB: double broad, double thick.

OM: oblique medium, oblique point, medium, generally used by left-handers or writing special fonts.

OB: oblique broad, slanted, thick, generally used by left-handers or when writing special fonts.

OBB: oblique double broad, oblique point, double thick, used for writing special fonts.

S: stub, also known as Italian nib, has a flat tip and is suitable for writing Western cursive characters. sdaoidj dko asjdlksajdkl ajslkd jkl asjdklasjkldjaskl