This is because European cups are small, about four fluid ounces, and usually the brewers are marked for these small cups.

这是因为欧式量杯是小杯，大约只有四液体盎司，通常咖啡机标示为这些小杯。

youdao

And at 1.8 fluid ounces, the whole thing comes in well under the TSA's carry-on liquid restrictions.

ENGADGET

According to the proposal, patrons would be able to buy multiple containers, but restaurants and other establishments would not be able to sell sugary drinks in cups or containers that are more than 16 fluid ounces.

WSJ: New York City Plans To Restrict Big-Size Soda Sales