Men's UA Threadborne Siro Muscle Tank

Style # 1289617
Height: Size: Fit: Loose
Mens UA Threadborne Siro Muscle Tank
  • Availability: 
  • Availability: 
Size and Fit Guide
Due to limited quantities, only 10 allowed per customer.
The product can't be added to the bag
Height: Size: Fit: Loose
Men's UA Threadborne Siro Muscle Tank

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


This is what makes our gear work harder—and smarter—than anything else out there.


The original innovation our founder dreamed up. This super-breathable fabric wicks sweat and regulates body temperature so you feel cooler, drier, and lighter than ever.

Review Summary

18 Reviews


Runs small Runs large


Min. Max.


Min. Max.

Nice top, great for the gym

Looks good but a little short in length - I’m 6’7”

Great quality

Good quality. Great fit. Reasonable price. Excellent delivery. Easy purchase

Perfect fit and feel

Great fit, relaxed and comfortable. Better than standard material.

Awesome tank

By far the best tank i have bought so far. comfortable, lightweight and doesnt cling even when sweaty.

Great shirt

Bought this shirt for my boyfriend, he absolutely loves the material and fit of the shirt.

This product works

I love the UA Tech sleeveless but no longer see them being sold so bought these. This item the fabric is comfortable but stretchy. Bring back the sleeveless Tech, well at least in my size [This review was collected as part of a promotion.]

This is a great product

The shirt fits and feels great. It's sized to fit just right. [This review was collected as part of a promotion.]

This workout top works great

Great workout shirt! Nice and cool on a hot day!!! [This review was collected as part of a promotion.]

Runs big.

It's OK. The shirt itself fits a little large. The arm holes are also bigger than I would prefer. Overall, it's a bit overpriced. [This review was collected as part of a promotion.]

Comfortable and good fit

I just got the shirt and it fits great. I prefer a roomy loose fit and this delivers. I'll be back for more. [This review was collected as part of a promotion.]