a more complicated molded design.
The absence of an obvious vent doesn’t necessarily mean the lid is defective. Air may enter through another opening or through a design that works differently.
What Happens If You Cover the Hole?
If you cover the vent on a lid that relies on it for airflow, you may notice that the drink flows less smoothly. Sipping could become more uneven because air has fewer ways to enter the cup.
However, the effect depends on the particular lid. Some designs can still function adequately without
