This is the $40 speaker-silencing gadget people are using to shut down China's crowds of dancing grandmas

• 100 million older women in China use square dancing as a way to socialize and exercise.
• People have long complained about the dancing grandmas' loud music, leading to noise pollution fines.

On most nights or early mornings in China, it's common to see large groups of elderly women flood into public parks and centers for square dancing. The ritual is linked to the Cultural Revolution of the 1960s and has proven a popular way for older people to exercise and socialize.

But many say the dancing grandmas play their music much too loud, an issue that has led to violent altercations, widespread noise complaints, and even arrests, The Guardian reported.

Now, adversaries of the dancers say they are using a $40 device to shut down the women's speakers from afar.

With some digging, Insider managed to locate a listing for the device on Taobao, a Chinese e-commerce site. One user who reviewed the product wrote that the tech is "very powerful," adding that now they have "no need to argue with the unreasonable group of square aunts" who "go around like bandits."

"There is nothing wrong with dancing when you are old," they wrote. "But it cannot affect other people."

Proponents of the gatherings say the women - many of whom live alone - have developed valuable friendships through square dancing and often go shopping and traveling together, according to the South China Morning Post.

One 19-year-old merchant told Vice News that he has sold 20,000 of the devices advertised online as "square dance sound noise jammer" and "anti-square dance nemesis remote," claiming to have personally stopped 36 groups of dancing grandmas with the object.

While the tool has been lauded as "magical" on Chinese social media, it looks to be identical in appearance to a $2 LED flashlight listed on Alibaba.

With a price tag ranging from $15 to $40, one listing instructs users to "turn on the device, and then aim at the square dance speaker. The operation is simple and the anti-noise effect is remarkable!"

One reviewer wrote that the purchase was a "waste of money," and that it only worked when used "very close" to the speakers, which they claimed to have turned off twice before the group noticed.

The increased public annoyance surrounding the dancing grandmas has led the Chinese government to introduce a noise pollution fine of approximately $78, according to the South China Morning Post.

A happy medium seems to have been found in Shanghai, where the dancing grannies are using Bluetooth headphones to create a silent disco, the SCMP report says.