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What are those blue dots on coin cell batteries?
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What are those blue dots on coin cell batteries?

Mark Frauenfelder
Nov 26, 2024
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Boing Boing
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What are those blue dots on coin cell batteries?
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Energizer coin cell battery with Color Alert coating

Yesterday a redditor named joshcam posted a photo of a coin cell battery with purple colored dots arranged in three concentric semicircles. They posted:

To the naked eye, these dots are an iridescent, deep purple, the kind of purple you see when you look at a black light.

There are three rows of dots run…

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