GROWING up, most of us chewed on pen lids or pretended the plastic feature was a mini whistle.
But turns out, the tiny holes in the colourful caps are designed for something else, according to one internet user.
., who regularly shares discoveries he finds interesting, took to Instagram to reveal why pen caps comes with small holes.
''Most people think it has something to do with the ink.
''But the actual reason is much more important than that,'' Zack said to his 213,000 fans on social media.
According to him, pen companies are legally required to add these tiny holes in the design.
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He went on to explain in a video: ''You see, it's just enough space for airflow if the cap gets stuck in someone's throat.''
With more 3.1million views, has gone viral, leaving many people stunned at the discovery.
One person commented: ''Same reason with lego head that always has hole in it.''
However, not everyone was so impressed, with one saying it wasn't anything revolutionary.
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''I thought this was common knowledge.''
It seems that in the recent months, more and more people have shared their newly-acquired knowledge, including what the 'E' symbol on their meat packaging stands for.
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With the cost-of-living crisis making food prices soar by 11.6%, more supermarket customers are paying attention to what they buy - after all, every penny counts.
Amongst those now carefully inspecting their bills and food items is Elaine Barker, a member of the popular on Facebook.
One day, after weighing the mince she had purchased, the woman came to a shocking discovery; one she decided to share to the fellow members of the group.
''NOT a coupon or bargain but maybe something to think about.....are we getting what we pay for?'' Elaine wrote in the caption of .
According to her, she had grabbed a 500g packet of lean beef steak mince.
Like the majority of us, she assumed that that's what she would be getting - half a kilo of the product she had paid for.
But despite what the packaging stated, she very quickly came to learn that rather than 500g of meat, she had instead purchased less than that.
''Bought what I assumed was 500g, as stated on the pack, but in reality got 456g!
''Not a lot of difference I know but it just makes me wonder,'' she continued in the caption above the snap which revealed the unpleasant discovery.
Social media users then came to conclude that the 'E' on the plastic packaging stands for 'estimated', leaving many furious.
''People moaning its only 50g yet if you bought a variety bag of 6 packs of crisp and only got 5 would you stil be okay with it [sic]?'' commented one person.
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"You bought a crate of 12 cans and got 10 is that okay?
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''We do get conned even when the times are hard and they call it a "living crisis" people should be more vigilant on where there wasting there money! [sic]''