Men's UA Threadborne Siro ¼ Zip

Style # 1289600
Height: Size: Fit: Loose
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Height: Size: Fit: Loose
Men's UA Threadborne Siro ¼ Zip

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Product DNA

Using new manufacturing techniques, Threadborne Siro fabric is built to eliminate distraction. We‘ve engineered it to keep the ideal distance between fabric and athlete, so it won't cling when wet and dries incredibly fast.
  • Loose: Fuller cut for complete comfort
  • Threadborne Siro fabric gives greater stretch & recovery, ultra-soft feel & more breathable performance
  • Material wicks sweat & dries really fast
  • Anti-odor technology prevents the growth of odor-causing microbes
  • Polyester
  • Imported

Review Summary

22 Reviews


Runs small Runs large


Min. Max.


Min. Max.

A great shirt!

I bought this for my husband. He is a body builder with very large arms and has trouble with a lot of shirts not fitting his arms (being too tight) and having to wear huge baggy stuff in order for them to not be too tight on his arms. This shirt is an exception. It is stretchy and flattering and helps wick away his sweat! He was able to get a medium and it works great for him!

Runs short, and shrinks.

So I am 6'3" and most clothes run short at the waist which is why I have started wearing UA clothes, because the fit is much better than other brands, overall. I love the fabric, as I would wear it against my skin, or over a light t-shirt, but the after a few washes, the sleeves began to shorten along with the waist. I own another Threadborne henley, that does not have this issue. I wonder if I got a bad one, but either way, everything about this line of clothing is right, except for the shrinking aspect.

Awesome 1/4 zip!

I own a ton of the UA 1/4 zip in different styles. Always stayed away from this one due to the price tag. Saw it on sale at the outlet so decided to try it. Fantastic fit and extremely comfortable. Bought the blue but would have bought more if they had them.

Love it, if it lasted

Extremely comfortable and fits great. Everything is perfect except for the problems after one wash. Fuzz balls all over it to the point that it looks years old. Also, the stitching is coming lose around both wrists. I am a huge Under Armour fan and a stockholder but have been disappointed with quality recently. I will not let my family buy anything but Under Armour, however, that may change in the future if you guys don’t bring your quality back.

Mixed feelings

Not that impressed with the material of the Raisin Red but love the Mako, not the same material as someone else mentioned.

Perfect Light Layer

These shirts are great but one thing that isn't really noted here is that there are really 3 types of this shirt and they vary a bit in appearance and fit. The first type is your basic plain fabric. Mako Blue is one of these. Look closely at it and you'll see there is no pattern evident on the fabric. These are my favorite type as they feel a little thicker and fit as I would expect. The next types are Herringbone. Arden Green and True Ink are this type among others. You can see if you look. This type is basically the same as the Plains, one thing to note is that the colors are much more subtle. They are grossly over represented in the posted images. For instance, True Ink looks pretty blue there, right? I got it and I thought they sent me the wrong one because it was mostly gray with some pale blue. Arden green (wearing presently) is similar -- would be nice to have these awesome colors completely and not muted as they are, but that's still fine. The last ones have horizontal stripes. These are newer colors like Morroccan Blue and Tourmaline Teal. These fit more like the Streaker 1/4 zips, that is, kind of odd across the chest (tight). The stripes are more pronounced in person to the point where I couldn't deal with it and returned them. They also feel ... thinner. I really thought it was a different shirt completely but I verified its the same product number on the tag. I had a few Streaker shirts that didn't work out for me for these same reasons, and sometimes I wonder if they really are them. Anyway, those don't fit me right so I can't buy them anymore. It's a shame they're nice colors

very impressed by this top. it does run large

really good top. v light and will dry quickly and wick sweat well. would give 5 stars except haven't had it for long enough yet. I'm usually on the low side of needing large size shirts - am really between med and large - so I go large. For this, unless you want to layer it over a tee shirt or something, I'd go down a "half size" unless you're pretty chunky for your size. When they say loose fit they mean it. Arms are very long too. Absolutely phenomenal service. Stuff was sent incredibly fast and arrives really quickly. Really impressed.

Grey is good, Blue not so much

I have 2 of these. One is grey and is awesome. Love the shirt. It is light but fits well and is just what I wanted. I liked it so much I also ordered the blue one. The blue one has pilled up after a few washes and looks old already, where as the grey one looks new still. I really like the color, but it is showing wear already, which is too soon I believe since the grey one is going strong.

Light, Thin, and Performs Excellent!

I was a little skeptical when I saw how thin this 1/4 zip was. I thought I was going to wear i on semi-cool days, however; I feel as though it has its own temperature gauge. I cannot explain the science behind it, but I feel like it matches your own body heat to keep you comfortable. I can wear it on semi-cool days, and I don't have to worry about it getting too hot. I also wear it on cold days, and it keeps me warm. This 1/4 zip is where its at. Easy to wear, and easy on the temperatures we cannot control. This zip is my go to when I don't know how the weather will turn out for the day, since it addresses all my needs. I have not tried working out in the zip, but I would not see a problem with it.


These fit well enough at large for us tall folks, but if this was available in tall it would make the product that much better.