What is the size of a standard envelope?

Chinese style 3 176* 125 16.

Western-style 3 162* 1 14 plus 16.

China Wind No.5 220* 1 10 positive degree 8.

Western-style No.5 220* 1 10 plus 8 degrees.

Chinese style No.6 230* 120 plus 8 degrees.

Western-style No.7, 229* 162, plus 8 degrees.

China Wind No.7, 229* 162, plus 8 degrees.

Western-style No.9, 324*229, plus 4 degrees.

China Wind No.9, 324*229, positive degree 4.