Compiled from 8 sources; we haven't tested this product ourselves yet. How we research
Quick answer
The uni Propus Window is a double-ended Japanese highlighter from Mitsubishi Pencil with a clear window in its 4.0 mm chisel, so you can see the text and stop exactly where you want. The other end is a 0.6 mm fine tip. Launched in 2000, it costs ¥132 (about US$0.80) in Japan and sits in our $ band.
On this page10 sections
The Propus Window, 138 mm capped; the window in the chisel shows the text underneath.
Product facts
Product
uni Propus Window double-ended highlighter (PUS-102T)
Plastic barrel and caps; felt chisel with a clear window and felt fine tip; water-based ink (Mitsubishi Pencil, Amazon)
Released
2000*
Price range
$under $5 per pen (multi-packs divided by the count)
Ink colors
Pink
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Notes on these facts
Made by Mitsubishi Pencil Co., Ltd. (Tokyo). Country of manufacture not stated: Mitsubishi Pencil's Japanese Propus Window pages and press releases (read on October 22, 2026), JetPens and Amazon US don't state a country of manufacture. Check the barrel or package. Price: example listing. Released: Mitsubishi Pencil's 2011 and 2015 press releases both say the Propus Window went on sale in 2000; the current PUS-102T code may be later.
Colors: names per Mitsubishi Pencil Japan, checked October 24, 2026. The five PUS-102T colors on Mitsubishi Pencil Japan's page (桃, 黄, 橙, 緑, 空色), translated. The 2011 Soft Colors and the PUS-103T color markers have their own codes and aren't listed. Tints were sampled from Mitsubishi Pencil's product photos. Tints are representative, not measured. Shops stock different colors.
Price bands are typical US retail, checked October 2026. Conversions to US dollars are approximate, at October 2026 rates (US$1 = ¥158 = ₩1,330 = NT$32.5 = CN¥6.7 = SEK 9.9 = DKK 6.7 = ₺49.6 = C$1.41 = A$1.43 = CZK 21.7; €1 = US$1.12; £1 = US$1.32; CHF 1 = US$1.21).
Key takeaways
The broad end is a 4.0 mm chisel with a window cut into the tip, and the fine end draws 0.6 mm (Mitsubishi Pencil).
Mitsubishi Pencil launched the Propus Window in 2000 and added five pastel Soft Colors on February 16, 2011.
The Q-Dry version, out October 30, 2015, dries in under a third of the time of uni's earlier ink, per the maker.
JetPens lists the Q-Dry at 138 mm (5.4 in) capped, 11.5 mm across and about 8 g.
Mitsubishi Pencil's Japanese list price is ¥132 (about US$0.80) a pen, or ¥660 (about US$4.20) for five.
What is the uni Propus Window?
It’s a double-ended highlighter from Mitsubishi Pencil (uni) with a clear window in the broad chisel tip, so the text stays visible while you mark it. Mitsubishi Pencil sells it with the promise that lines don’t run past the words you meant to highlight.
The company says the Propus Window went on sale in 2000 and became a favorite with students. JetPens picks the quick-drying version as its best highlighter for left-handed writers, and on Amazon US the five-color PUS-102T set had 1,609 ratings on October 22, 2026.
uni Propus Window specs
Spec
Value
Maker
Mitsubishi Pencil Co., Ltd., Tokyo
Model
PUS-102T (standard); PUS-103T (color markers); Q-Dry version
Broad tip
4.0 mm chisel with a window (Mitsubishi Pencil)
Fine tip
0.6 mm (PUS-102T); 0.4 mm plastic tip (PUS-103T)
Ink
Water-based (Amazon)
Length
138 mm (5.4 in) capped, 120 mm (4.7 in) uncapped (JetPens, Q-Dry)
Diameter
11.5 mm (0.45 in) max (JetPens)
Weight
About 8 g with ink (JetPens)
Japan list price
¥132 (about US$0.80) each, with tax
Price band
$ (under $5 per pen)
Made in
Not stated
The three Propus Window line widths Mitsubishi Pencil publishes, magnified.
How does the window in the tip work?
A clear section is molded into the felt chisel, so the printed letters show through it as you draw. With an ordinary chisel, the tip hides the end of the word, and most people overshoot.
Mitsubishi Pencil says the window lets you mark only the part you want to check. The window is on the broad end only; the 0.6 mm fine end is a plain felt tip for underlining or writing small notes.
What is the Propus Window Q-Dry?
It’s the quick-drying version, launched on October 30, 2015, with what uni calls Q-Dry ink. Mitsubishi Pencil says the ink dries in under a third of the time of its earlier highlighter ink, so it doesn’t smear on coated textbook pages or your hand.
At launch, uni listed it at ¥130 (about US$0.80) before tax in sky blue, green, yellow, orange and pink, plus yellow and pink in a black barrel. Uni says the colored particles still fix firmly to the paper, so the line resists rubbing.
Which Propus Window colors are there?
Five standard fluorescent colors, five pastel Soft Colors and fifteen color-marker shades. The standard PUS-102T comes in pink, yellow, orange, green and sky blue.
Line
Colors
Fine tip
Standard PUS-102T
Pink, yellow, orange, green, sky blue
0.6 mm
Soft Color (2011)
Yamabuki, lime, aqua, lavender, sakura
0.6 mm
Color marker PUS-103T (2019)
5 basic, 5 light, 5 smoke
0.4 mm
The 2019 color markers swapped the felt fine tip for a 0.4 mm plastic one that Mitsubishi Pencil says suits writing words, not only underlining.
How does it compare with other highlighters?
It’s the pick when you need to stop exactly at a word; pastel and refillable highlighters win on other things. The Zebra Mildliner has softer colors and a bullet fine end, while the Monami Essenti Soft is a slimmer single-tip pastel.
For notes written in water-based gel ink, the Zebra Justfit Mojini Line is built not to smear the ink. All three sit in our $ band.
Where is the uni Propus Window made?
Mitsubishi Pencil doesn’t say on the pages we read, and neither do JetPens or Amazon US. The brand is Japanese: uni is Mitsubishi Pencil’s brand, based in Tokyo.
Check the barrel or package if the country of manufacture matters to you.
Frequently asked questions
Why does the Propus Window have a hole in the tip?
It's a clear window molded into the chisel. Mitsubishi Pencil says you can see the letters through it while you draw, so the line doesn't run past the words you want to mark.
What tip sizes does the uni Propus Window have?
The broad end is a 4.0 mm windowed chisel. The fine end is 0.6 mm on the standard PUS-102T and 0.4 mm on the PUS-103T color markers launched in 2019.
Is the Propus Window good for left-handed people?
The Q-Dry version is JetPens' pick for left-handed writers, because Mitsubishi Pencil says its ink dries in under a third of the time of its earlier highlighter ink, so a trailing hand smears it less.
What are the Propus Window Soft Colors?
Five pastel shades Mitsubishi Pencil added on February 16, 2011: yamabuki (golden yellow), lime, aqua, lavender and sakura pink.
How much is a Propus Window in Japan?
Mitsubishi Pencil lists ¥132 (about US$0.80) with tax for one pen, ¥396 (about US$2.50) for three colors and ¥660 (about US$4.20) for five.
Is the uni Propus Window made in the USA?
No. It's a Japanese uni product; neither Mitsubishi Pencil nor the US retailers we checked state the factory country.
