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also called crown cap, crown cork, beer cap

About
A bottle cap is a small circular seal designed to keep beverages fresh and prevent liquids from leaking.
Traditional crown caps for glass bottles follow a standard size, while screw-on plastic caps for soda jugs are often slightly wider or taller. Larger wide-mouth beverage containers use caps exceeding 1.5 inches (3.8 cm) across, whereas beer bottle tops remain compact. Despite weighing less than a tenth of an ounce, each tiny metal disc is shaped with fluted edges to securely hold back carbonation pressure.
From Wikipedia
A bottle cap or bottle top is a common closure for the top opening of a bottle. A cap is sometimes colorfully decorated with the logo of the brand of contents.
Read more on Wikipedia →Text from Wikipedia’s “Bottle cap” article, CC BY-SA 4.0.
1 on the site
Weight
0.078 oz (2.2 g)
Quick answer
A standard bottle cap measures about 1.3 inches (3.2 cm) across, 0.24 inches (0.6 cm) tall, and weighs 0.08 ounces (2.2 g). That makes it roughly the diameter of a half-dollar coin.
Typical figures, the same ones every comparison on the site uses; real ones vary.
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