What the red Christmas light is really for?

The little red-nosed bulb that comes with strings of holiday lights has an unassuming function people are just now discovering, thanks to a “revelation” on TikTok

A woman shared a video demonstrating how the little red light is actually intended to make other lights glimmer.

“I was today years old when I found out what these are for,” the light scholar, who goes by the handle @VizNelly on TikTok, captioned the illuminating video.

First, she removes a single bulb from a string of lights and replaces it with the red one

“Wait for it,” she says, building up the holiday hype. Then, the strand of lights start flickering, the festive DIY video shows.

Viewers were shocked — with many thinking the little red bulb was simply a spare, should one light stop shining.

“I thought they were replacement bulbs if one burnt out,” one commenter wrote of the blinking lights.

“Dude, all they had to do was write something somewhere on the box. I wasted so many years not knowing this.”

Despite the enlightening revelation for many Gen Zers, some viewers were quick to point out the discovery is nothing new.

“As someone who grew up in the 90s … I thought everyone knew this. We didn’t always have remote control lights!” the elder millennial chimed in.

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