A woman walking away on a sunlit gravel path beside a stone wall, wearing Halo FS1 in Lumen Mist with the coral Halo Circle Mark on her back

The shirt that turns
sunlight into red light.

Halo — just get dressed and it’s on.

Halo — just get dressed
and it’s on.

Shop Halo FS1 — $98
  • 30%+ more red lightMore of what your body wants
  • Always UPF 50+Finally UV is put to work
  • 4°F+ coolerLess heat, more time outside

The technology

UV2RED™

Built into the fiber, UV2RED converts UV and high-energy light into red and near-infrared light, the wavelengths your body uses. No batteries, no charging, no scheduling.

UV in. Red out. The fabric converts it. Your body takes it from there.

UV in. Red out.

Your body takes it from there.

Measured. Not claimed.

Verified in lab and sun.

Light
↑30%+red & NIR

More red and near-infrared light reaching your skin than without UV2RED.

Spectrometer · full sun · Charlotte, NC

UV
↓98%of UV stopped

UPF 50+ — UV isn’t just stopped, it’s converted. Same photon, different job.

AATCC 183 · every UV2RED fabric

Heat
↓4°F+cooler

Than comparable fabric in full sun. Energy leaves as light, not heat. Up to 12.4°F in our tests.

Thermocouple under the fabric · 1,100+ W/m²

Made for light

Take away the light.
Still a better shirt.

Lightweight, soft, and breathable. The textured, micro‑perforated knit keeps air moving and feels comfortable against the skin. Matte, never shiny. Relaxed without feeling oversized. Built to be the shirt you reach for even without the technology.

Lightweight, soft, and breathable. Micro-perforated for airflow. Matte, never shiny. Relaxed, not baggy.

“Fishing in the Everglades. Heat index hit 100 and it felt like 90.”
Billy R., Florida
“I'm on court seven or eight hours a day. It doesn't feel like a long sleeve. I've tested it.”
Philip N., teaching tennis pro
“Better than the Lululemon long sleeve: the fit, the fabric, and it holds up after washing.”
S. Leitner
Halo FS1 Midnight Sun fabric close-up, the coral Halo Circle Mark at the upper leftMicro‑perforated knit
The coral mark inside the back neck of Halo FS1 — generated concept frame
Halo FS1 Skywave sleeve pushed to the elbow in sun — generated concept frame

Pick your light.

Every color — light optimized, UPF 50+.

Limited time: 2 FS1s for $169. Your second is just $71. Free shipping.

30-day returns

Real life

Here's what your shirt could be doing today.

When you’re in a Halo, the sun works for you. See today’s UV2RED Score and forecast for your area.

— UV2RED Score
Very good
Best window 11 am – 3 pm
Lumen Mist — Halo FS1Halo FS1
Shop Halo FS1

Estimates based on today's forecast

Why it matters

We are, literally, creatures of light.

We are, literally, creatures of light.

Athletes, scientists, physicians, artists — all connected by light, in their own words.

Huberman: long wavelength light is the key
Scientist
Andrew Huberman · The Megyn Kelly Show Huberman: long wavelength light is the keyHuberman says the long wavelength part of sunlight is the key, and the trick is getting it without too much UV.
Djokovic: recovery takes more time now, red light still on his list
Athlete
Novak Djokovic · Wimbledon press conference Djokovic: recovery takes more time now, red light still on his list
Rick Rubin: sun to start the day, only red light after sunset
Artist
Rick Rubin · Huberman Lab Rick Rubin: sun to start the day, only red light after sunset
Laird Hamilton: red light makes up for the sun we're missing
Athlete
Laird Hamilton · The Shawn Ryan Show Laird Hamilton: red light makes up for the sun we're missing
Hear them all at LightTalk