Niroku Masaki had a vision. In 1887, he wanted to start a pencil company that would create a quality product combining function and style. Through the years, uni has continued to innovate using advancements in technology while listening to consumers.

W- Speed Engine

When uni introduced the original Kuru Toga mechanical pencil, we took a moment to accept the accolades then set to work improving it. We are proud to introduce the W-Speed Engine.

The W-Speed Engine is the mechanism that makes the lead turn. Every 20 strokes, the engine turns the lead 18%. This keeps the point constantly sharpening against the paper. That’s twice the speed of the original Kuru Toga.

Each ADVANCE has a window so you can see the engine in action. It also have a metal sleeve that retracts as you write. This pipe helps protect the lead from breaking while keeping the perfect amount of lead visible.

Available in the uni JETSTREAM 4&1 + Kuru Toga ADVANCE Box exclusively on Amazon.

W-Speed Engine

Nano Dia Lead

Over 130 years ago, Niroku Masaki founded a pencil company that would eventually be known as uni. Creating superior wooden pencils that combined style and function, Masaki wanted to elevate the pencil. As a visionary, we like to think he would be impressed with how far we’ve come. Our Nano Dia lead is the kind of technology he imagined but lacked the technology to create.

Nano Dia lead is blended with millions of nanodiamond particles and silicone oil resulting in a strong lead that writes smooth. It’s designed to work in most mechanical pencils, but we particularly like it in the uni Kuru Toga ADVANCE. When combined with the ADVANCE's metal sleeve tip, breakage becomes a thing of the past.

Nano Dia Lead

D1 Size Refills

After introducing the multi-function uni JETSTREAM pens, we listened to the feedback. One popular request was to make a multi-function JETSTREAM using D1 sized refills. While the larger size of pens like the JETSTREAM 4&1 is perfect for some, others wanted a slimmer profile, but with the same quality JETSTREAM ink.

We love the enthusiasm people have for JETSTREAM ink and understand how attached a person can become to a particular pen body. We decided to make that request a reality!

Combined with other feedback, we decided to develop a pen that A) used D1 size JETSTREAM ink B) took advantage of the D1 dimensions and C) looked good doing it. The uni JETSTREAM PRIME was born!

JETSTREAM D1 Ink refill


If you’ve never tried uni JETSTREAM ink, we feel we need to caution you. JETSTREAM ink is so smooth yet crisp with rich, lasting color that once you’ve tried it, you’ll be disappointed by other ink. Go ahead and try it for a few days then pick up an average ballpoint pen. As you scratch along the page, don’t be angry at the pen you’re using. It’s average for a reason.

JETSTREAM ink is a hybrid ink that combines the best features of rollerball ink with the convenience of ballpoint ink. Balancing low-viscosity with uni’s Super Ink technology and extra pigment, ink flows smoothly, dries instantly, and provides bold color.

The pigment binds with the cellulose in the paper meaning the ink will last as long as the paper. It resists the sun, liquid, and even time. JETSTREAM ink exceeds the requirements for ISO 14145-2 so it’s perfect for signing documentation.

JETSTREAM Ink colors