technology?

What is this?

Can you imagine what this is? Put your smartphone into the slit in the center and you can listen to the sound much better. Yes, it is a very primitive speaker made of two paper cups, with a toilet paper roll as its core. I usually put this in my kitchen and listen to the news and music. And I sometimes bring them to my students' lessons so that we can use them for listening practice. Then they like the change of the sound very much and even say, "Wow, this is Japanese technology, indeed!"
 
 
 
 
 
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