Watching the liquid move and bubble as it reacts to warmth makes it easy to forget that this is actually a pen!

When it comes to the world of stationery, Japan has given us some of the most unique items we’ve ever seen. There are erasers that take on different hairstyles, magnetic arrows you can write messages on, and pencils that bloom into edible plants in the garden. For some stationery lovers in Japan, though, it’s the rare products from years ago that hold a special allure, and one of those items is the Coffee Siphon Ballpoint Pen.

It might look like a modern gadget, but this pen is no longer on the market, existing only in the homes of those lucky enough to purchase the pen when it was available. Twitter user @higurashikinoko recently shared a short video featuring the pen, which was given to her by her father about 20 years ago, and the clip shows how the brown “coffee” liquid inside moves between the two spheres on top, exactly like a coffee siphon.

Since it appeared online, the clip has been shared and retweeted more than 20,000 times, surprising people who have never seen the pen before and taking everyone else on a fond trip down memory lane.

“These were all the rage when I was a junior high school student in the 80s.”
“It’s my first time seeing these and now they’re not available anywhere!”
“I remember buying this for 1,000 yen at a souvenir shop during a school excursion in elementary school!”
“I’ve had one of these for years and I love it but I still don’t know how it works.”

According to the Sailor fountain pen company, who sold the product in years gone by, the liquid in the vessel has a low-temperature boiling point, which allows it to move just with the touch of a human hand. Like a coffee siphon, the liquid is pushed upwards when the lower vessel is heated. Touching the top vessel forces the substance to move downwards.

To see another video of the pen at work, check out the short clip below.

Source: Byoukan Sunday
Top Image: Twitter/@higurashikinoko