Compiled from 12 sources; we haven't tested these products ourselves yet. How we research
Quick answer
Both are retractable, refillable Japanese pens sold as quick-drying and smear-resistant, which is why left-handed writers argue about them. The uni-ball Jetstream RT is a ballpoint with low-viscosity oil-based pigment ink that uni markets as water-resistant. The Pentel EnerGel RTX is a gel pen with a darker, wetter line, needle tips and down to 0.3 mm.
On this page10 sections
Hybrid-ink ballpoint above liquid-gel pen, drawn in proportion.
uni-ball Jetstream RT Retractable Ballpoint (0.5 / 0.7 / 1.0 mm; SXN-210): Made by Mitsubishi Pencil Co., Ltd.. Made in Japan: per US business-supplier spec sheets for items 62152 (0.7 mm black), 62153 (0.7 mm blue) and 73834 (1.0 mm red), all listing Japan; Unsharpen also lists Japan. uni's US store, uni-ball UK and Mitsubishi Pencil's Japanese site don't state it. Source. Released: Mitsubishi Pencil's February 17, 2011 press release says the Jetstream Standard went on sale in Japan in July 2006; we found no separate US launch date for the RT.
Pentel EnerGel RTX (BL77, BLN75, BLN73, BLN77, BL80): Made by ASTRUM Corporation (Tokyo), called Pentel Co., Ltd. until April 1, 2026; Pentel remains the brand. Made in Japan or Mexico: Pentel of America's 2022 product catalog gives the origin of the EnerGel RTX (BL77 metal tip and BLN73/75/77 needle tips) as 'Japan / Mexico' without saying which SKU comes from where. Retailer listings match: OfficeSupply.com lists Mexico for one RTX listing. Pentel's Japanese product page doesn't state a country. Check the package of the exact pen you buy. Source. Released: Year the EnerGel line launched, per Pentel's Japanese news release of August 7, 2026. Pentel's Japanese magazine says it was sold only outside Japan at first, with Japanese sales starting in 2003. We found no separate debut date for the US RTX model.
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
Ink: Mitsubishi Pencil classes Jetstream as a low-viscosity oil-based ballpoint; Pentel calls EnerGel a low-viscosity liquid gel ink with 3 times its usual gel ink's lubricant.
Sizes: Jetstream RT 0.5, 0.7 and 1.0 mm in the US; EnerGel RTX 0.3 and 0.5 mm needle, 0.7 mm needle or metal, and 1.0 mm metal.
uni-ball UK lists the 1.0 mm Jetstream RT at 141.4 mm (5.6 in) and 13.8 g; JetPens lists a 0.5 mm EnerGel RTX needle tip at 14.8 cm (5.8 in) and 13 g.
Scale: Mitsubishi Pencil says the Jetstream series sells over 100 million pens a year; Pentel says EnerGel passed 1.6 billion pens sold by August 2026.
Refills: Jetstream SXR-5, SXR-7 and SXR-10; EnerGel LRN3, LRN5, LRN7, LR7 and LR10.
What is the difference between the Jetstream and the EnerGel?
The Jetstream is a ballpoint with thin oil-based ink; the EnerGel is a gel pen with thin water-based “liquid gel” ink. Both makers set out to fix the same problems, smearing and slow drying, from opposite directions.
Mitsubishi Pencil launched the Jetstream in Japan in July 2006, and the uni-ball Jetstream RT is its refillable US model. Pentel launched EnerGel in 2001, first outside Japan; the Pentel EnerGel RTX is its main refillable US pen.
How do the Jetstream RT and EnerGel RTX compare?
They’re the same size and price band; the ink, the tips and the water claims differ.
uni-ball Jetstream RT
Pentel EnerGel RTX
Pen type
Ballpoint (oil-based, low viscosity)
Gel (liquid gel, low viscosity)
Maker’s ink claim
Quick-drying; Super Ink resists water, fading, check washing
Quick-drying, smudge-resistant
US tip sizes
0.5 · 0.7 · 1.0 mm
0.3 · 0.5 needle · 0.7 needle or metal · 1.0 metal
Length
141.4 mm (5.6 in), 1.0 mm (uni-ball UK)
14.8 cm (5.8 in), 0.5 mm needle (JetPens)
Weight
13.8 g (uni-ball UK)
13 g (JetPens)
Refill
SXR-5 · SXR-7 · SXR-10
LRN3 · LRN5 · LRN7 · LR7 · LR10
Japan list price
¥275 (about US$1.70), rubber-body 0.7 mm
¥275 (about US$1.70)
Made in
Japan (US supplier sheets)
Japan or Mexico (Pentel of America)
Price band
$ (under $5)
$ (under $5)
Which dries faster?
Both are sold as quick-drying, and neither maker publishes a dry time in seconds. Pentel says EnerGel ink has three times the lubricant of its usual gel ink and soaks into paper quickly; Mitsubishi Pencil calls Jetstream’s oil-based pigment ink quick-drying.
Ballpoint ink sits in a thinner film than gel, so a Jetstream line usually has less wet ink to smear. In a 2011 blog test by Mark Dominus at leancrew.com, cited in our Sarasa Clip vs EnerGel comparison, the EnerGel smudged only if touched within a second or two.
Which has the finer tip?
The EnerGel, at 0.3 mm with a needle tip; the Jetstream RT’s finest US size is 0.5 mm. A needle tip is a long thin tube around the ball, which makes the point easy to see in small planner boxes.
US sizes of each pen to scale, with their refill codes.
Line width runs finer than the ball on both, and ballpoint lines are thinner than gel lines at the same size. A 0.7 mm Jetstream and a 0.5 mm EnerGel are closer on paper than the numbers suggest.
Which holds up to water and fraud?
The Jetstream RT. uni markets its Super Ink as resistant to check washing, water, fading and document alteration, and Mitsubishi Pencil describes it as a pigment ink.
Pentel doesn’t say whether standard EnerGel ink is pigment or dye and makes no water claim. For permanence, Pentel UK sells a separate LRP7 permanent refill that fits EnerGel pens.
Which should you buy?
Pick the Jetstream RT for checks, forms, cheap paper and the least smearing; pick the EnerGel RTX for a darker gel line and needle tips.
uni-ball Jetstream RT: a ballpoint that writes like a gel pen, with water-resistant ink. Pair it with our Jetstream vs G2 comparison; it is also our top pick among the best ballpoint pens.
US supplier spec sheets list the Jetstream RT as made in Japan; Pentel of America gives “Japan / Mexico” for the EnerGel RTX. Pentel’s catalog doesn’t say which pack comes from where, so check the package.
Frequently asked questions
Is the Jetstream a gel pen?
No. Mitsubishi Pencil classes it as a low-viscosity oil-based ballpoint; uni-ball's US marketing calls the ink a hybrid because it aims for gel-like smoothness with ballpoint drying.
Which is better for left-handed writers, Jetstream or EnerGel?
Both are marketed for it. Pentel recommends EnerGel for left-handed writers, and uni says Jetstream ink resists smudges. Our left-handed roundup names the EnerGel 0.5 mm overall and the Jetstream as the best ballpoint.
Is EnerGel ink waterproof?
Pentel makes no water-resistance claim for standard EnerGel ink. For permanence Pentel UK sells a separate LRP7 permanent refill; uni markets Jetstream RT ink as resisting water, fading and check washing.
Can you put an EnerGel refill in a Jetstream?
No. The Jetstream RT takes uni's SXR refills, and the EnerGel RTX takes Pentel's LR and LRN refills; each fits its own maker's pens.
Which writes darker, the Jetstream or the EnerGel?
Gel ink usually lays down a darker, wetter line than ballpoint ink, and Mitsubishi Pencil says the newer Jetstream ink is twice as dense in black as before. We haven't compared the two lines under a loupe yet.
What is a needle tip?
A long, thin metal tube around the ball that makes the point easy to see. Pentel's codes with an N, such as BLN75, are needle tips; the Jetstream RT has a standard cone tip.
Which is better for checks and signatures?
The Jetstream RT. uni says its Super Ink resists check washing, water, fading and alteration; Pentel makes no such claim for standard EnerGel ink.
