Things are getting real scientific around here, but don’t you worry, OROS isn’t going to require a PhD for you to enjoy the benefits of their unique Solarcore gel insulation used with the Explorer 1/4 Zip pullover.

OROS Explorer 1/4 Zip Pullover Features:

  • Solarcore 2mm insulation panels on front and rear
  • Panels also provide wind protection
  • 1/4 zip design with single chest pocket
  • Thumb loops for added hand warmth
  • Stretch knit fabric (54% polyester, 40% recycled polyester, 6% elastane)
  • MSRP: $120
OROS Explorer 1/4 Zip Pullover Running Review

The Explorer is just the ticket for cold-weather trail running.

I’m no astronaut, but Solarcore is legit

Over the years, I’ve tested plenty of one-off products. At times, they are awesome examples of entrepreneurs who are drinking too much Kool-Aid, but sometimes you find a gem; something that really works. This experiment was the OROS Explorer 1/4 Zip pullover with its unique and space-age (literally) Solarcore insulation. It’s the same stuff used to protect astronauts from the extreme cold of space, just optimized for apparel.

The Explorer 1/4 Zip is billed as a “do-it-all” mid/outer layer suitable for all types of cold-weather adventures. As an outer layer, the Solarcore panels on the front and back add warmth (more on that later) and wind protection. At 2mm thick, the panels are noticeable, but not overly-clunky. I thought it would feel like wearing body armor, but it surprisingly moves with you and adapts to your body’s contours really well. I’d like it a little more snug, but it’s good overall.

OROS Explorer 1/4 Zip Pullover Review

The collar height is nice, but the diameter is too wide.

Looking at the web site, the sizing seemed generous. At 5’11” and 170 lbs, I’m squarely in the MLarge camp. (Yeah, I’m a tweener and it’s frustrating with all tops from every brand.) With the OROS Explorer 1/4 Zip, I went with the medium and it proved to be a solid choice. The hem length is good and chest fit is about what I expected (a touch loose, but not baggy) and the arms fit just about right (with a small caveat).

The fabric of choice feels soft and cozy. It’s a midweight stretch knit and works well as both an outer and mid-layer. Moisture does transfer away from it, but it’s not the fastest-drying fabric out there. That dry time is noticeable on the front/back where the Solarcore panels are. Hanging it up to dry after a lunch run will still leave it slightly damp 4 hours later.

OROS Explorer 1/4 Zip Hem Length

The hem length is great on the size medium.

When out in the elements, the Solarcore panels are magical. The warmth provided is incredible and it does still breathe pretty well. I haven’t felt swampy or excessively-hot during my test runs. When out on a cold trail run, body warmth is maintained, but what’s cool about it is how the insulation kicks in when resting. As I stopped to take photos on the trail, Solarcore maintained warmth. With most other fabrics, stopping means things are going to get cold unless I put on an outer shell. But, I felt warm even though the fabric was pretty saturated.

That warmth when stopped mid-run is pretty awesome and is 100% due to the Solarcore panels because my saturated arms were mighty chilly when the winds picked up.

OROS Explorer 1/4 Zip Thumb Loops

Thumb loops are nice, but the sleeves could be a touch longer.

There are a few things I wish were better. Something that’s common with long-sleeve layers that feature thumb loops is sleeve length. If you’re going to include thumb loops, go ahead and add an inch to the length. Its always better to have a little extra as opposed to feeling stretched with use (I have a proportionate wingspan). I do also wish the collar were a little more snug and the zipper of a higher quality. I had a gap between my neck and the collar and wished for a little more weather-tight fit.

The Good

  • Solarcore insulation panels work wonderfully
  • Feels comfortable next-to-skin
  • Maintains warmth when stopped
  • Wind protection is a great bonus
  • Outer or mid-layer (you choose)
  • Flatlock seams are always nice

The Bad

  • Could have longer sleeves
  • Collar diameter is generous
  • Fit is a touch boxy

The Bottom Line: OROS Explorer 1/4 Zip Pullover

OROS is clearly passionate about their Solarcore insulation and the OROS Explorer 1/4 Zip pullover is a great execution of the material. It’s flexible and breathes pretty well overall while maintaining warmth when active and stopped during a run. Yeah, it’s a little quirky, but the folks at OROS are onto something here. I like it and have enjoyed using it as both an outer layer and mid-layer for cold-weather trail running.

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About Author

A native of the Pacific Northwest, Jason quickly developed a love for the outdoors and a thing for mountains. That infatuation continues as he founded this site in 1999 -- sharing his love of road biking, mountain biking, trail running and skiing. That passion is channeled into every article or gear review he writes. Utah's Wasatch Mountains are his playground.

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