12 fl oz and 355 ml are nearly equivalent. Proof is shown below.
1 fluid ounce is equivalent to 29.5735 millilitre
29.5735 ml
12 fl oz x --------------- = 354.882 rounded to the nearest ones will be 355 ml.
1 fl oz
OR
1 millilitre is equivalent to 0.033814 fluid ounce
0.033814 fl oz
355 ml x ------------------ = 12.00397 or 12 fl oz.
1 ml
12 fl oz and 355 ml are nearly equivalent.