Air Mail unused 1921 (Nov.) Air 35c., 2¾mm. setting (3, one with no stop after "1921", another with no stop after "1921" and first "1" of "1921" below "f" of "Halifax") and 1½mm. setting (2, one with no stop after "1921"), good to fine mint. S.G. 148, a, b, f, g; 570