Uni Power Tank 0.7 Review

The Power Tank is one of those cheap, disposable pens. And to save money, companies are going have to cut corners somewhere, so it makes sense to wonder. Is the pen scratchy? Is it ergonomic? Is the ink of good quality?

Our editing department purchased uni’s ever-popular Power Tank, contacted three stationery specialists, and sought to answer the above questions. We also looked up information about refills. This is what we learned during testing.

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mybest US Editors
  • Last updated: 04-04-2022
Table of Contents

What Sets the uni Power Tank Apart from Its Competitors?

What Sets the uni Power Tank Apart from Its Competitors?
The Power Tank is known as a “pressurized” ballpoint pen. What that means in plain language is every time you click on the pen, you’re generating compressed air, which forces the ink out the tip.
Since the Power Tank doesn’t rely on gravity to draw out ink (unlike traditional pens), you can write with the pen facing up or horizontally; the system also keeps water from seeping in through the tip, which helps when you write on wet paper.
It doesn’t look that much fancier than your average Office Depot pen, but it’s nifty for those who need to write outdoors or standing up. You can get the pens in 0.5, 0.7, or 1.0; the ink comes in black, which we tested, as well as red and blue.

Putting the uni Power Tank to the Test

Putting the uni Power Tank to the Test
We teamed up with three stationery specialists and put the Power Tank to the test. Specifically, we were looking for the five following factors.
Test ①: Design
Test ②: Grip
Test ③: The Feel of Writing
Test ④: Ink Depth and Color
Test ⑤: Drying Speed

Test ①: Design

Because isn’t a pen just another accessory?

Practical, but We Wish the Grip Weren’t So Bulky

Practical, but We Wish the Grip Weren’t So Bulky
There’s nothing revolutionary about the design. The Power Tank features a semi-transparent barrel with a black grip and clip. There’s a window carved into the grip, so you always know how much ink you have left.
So, overall, not much to complain about. Now, the grip is quite ungainly and rough when compared to the body. That might bother those of you who like sleek, clean-cut pens.

Test ②: Grip

Because who wants to write with an uncomfortable pen?

Thick Grip and Well-Balanced Pen for Firm Writers

Thick Grip and Well-Balanced Pen for Firm Writers
If you like soft grips, then this pen isn’t for you. The grip on the Power Tank is thick and sturdy, so it’ll stand up to a lot of pressure.
We balanced the pen on our finger to look for the center of balance. It hovered near the middle, just slightly closer to the tip, which means the pen should be easy to control no matter how you hold it.

Fit is Ideal for Gloved Hands

Fit is Ideal for Gloved Hands
In Japan, the Power Tank is especially popular among those who wear work gloves and others who take their writing outdoors. We were therefore curious how it would feel to write wearing knitted gloves.
Because the grip was thicker than usual and quite grippy as well, we had no issue. If you’re sick of having to remove your gloves every time you jot down some notes, then the Power Tank may be of some help.

Test ③: The Feel of Writing

Because pens write. And the Power Tank’s known for being an especially rugged instrument, so we put it through some interesting tests.

Ink Flow Starts Shaky but Then Smooths Itself out

Ink Flow Starts Shaky but Then Smooths Itself out
So when we first started writing, ink flow was kind of shaky and our strokes thinned out in places. However, give the pen a bit to warm up after you take it out of the package–doodle some loops in the corner of the page or something–and afterwards, the flow should stay pretty consistent. The ink came out smooth and the tip skated easily against the page.
All successive writing tests went fine. We also didn’t have any issues with the ink balling up or pooling in places, so you won’t need to worry about smears or having to frequently wipe off the nib.

Writes Well, No Matter What Direction the Tip is Pointing

Writes Well, No Matter What Direction the Tip is Pointing
This is the Power Tank’s selling point, so we had to test it out. We held a notebook against a wall and doodled on it, making sure that the tip of the pen was facing slightly upwards. And just as promised, the ink came out smoothly. Not once did the color fade and not once did the nib start scratching on the paper.

Also Writes Well, No Matter What the Temperature

Also Writes Well, No Matter What the Temperature
The Power Tank also claims that it can write in below freezing temperatures. So, to test that out, we stuck the pen in the freezer and left it there overnight. If the Power Tank were a typical pen, then the ink would turn to ice and leave us with a cold stick, not a writing instrument.
We came in the next morning, retrieved the pen, and started writing with it immediately, with frost still clouding over the barrel. Took us a few seconds to get the ink flowing, but after that, we had no problems. We aren’t sure how practical that would be for most people, but if you do ever need to take notes into the snow or in cold storage, you know what pen to use.

Test ④: Ink Depth and Color

Because the ink is what gives shape to your words.

Comes out to a Very Average Black. May Appear Thin to Those who Like Particularly Dark Ink

Comes out to a Very Average Black. May Appear Thin to Those who Like Particularly Dark Ink
We compared the ink to that of uni’s other top-seller, the Jetstream. The one on top’s the Power Tank; the one below is the Jet Stream. The Power Tank was noticeably thinner and lighter.
To be fair, the Jetstream’s known to have very dense, dark ink, so we’d say the Power Tank has “averagely black” ink.

Test ⑤: Drying Speed

Because what’s the point of pretty ink that doesn’t dry?

Dries in the Blink of an Eye

Dries in the Blink of an Eye
We scrawled “mybest” onto notebook paper and immediately went over it with a highlighter. There was pretty much no smearing–you can even still see the little chips in the ink.

Works Well in Wet Environments as Well

Works Well in Wet Environments as Well
We wrote onto a sheet of notebook paper and then spilled water over it, but there was no bleeding. We then tried writing onto an already wet page, but still, the ink came out with little issue.

The Final Verdict: A Rugged Little Pen that Works No Matter What Trials You Put It Through. The Power Tank Gets Our Seal of Approval

The Final Verdict: A Rugged Little Pen that Works No Matter What Trials You Put It Through. The Power Tank Gets Our Seal of Approval
You can use the Power Tank outside in the rain or snow. You can write standing up or while wearing gloves. It might not look like the most bewitching pen, but the Power Tank’s charm lies in its features. Its ink flows smoothly no matter the situation or the angle at which you hold the pen. It also dries quickly, so it’s a leftie-friendly instrument.

When Getting Refills, Make Sure the Product is Labeled “SNP”

Mitsubishi Pencil uni Ball Pen Refills 1

Mitsubishi Penciluni Ball Pen Refills

0.7 mm

$1.65

Refills for the Power Tank are available in Japan for 100 yen (~$1) apiece. You can get them in 0.5, 0.7, and 1.0. They’re all the same diameter and length, so you can switch one out for another.
There’s three colors in total: black, red, and blue. Unfortunately, blue isn’t available in 0.5, but you’re still given a fair amount of choice. Just make sure you look for the three letters “SNP” on the packaging–that means that the refill’s for the Power Tank and not some other pen.

Interested in Learning about Other Pens? Check Out Some More Articles Below

Interested in Learning about Other Pens? Check Out Some More Articles Below
We’ve got a bit of a stationery addiction. If you do too, you’ll probably enjoy checking our other reviews and recommendations.

Summary

We put the uni Power Tank to the test. We were impressed by the sheer number of situations in which it worked–whether it be wet, upside-down, or frozen. Overall, it’s a worthy purchase.

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