React Outlast® Underscrub
React Outlast® Underscrub
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Details
Details
Thermoregulating underscrub uses NASA-developed Outlast® yarns to keep you cool when you're running around and warm in chilly environments. Equipped with exceptional stretch and recovery.
- Slim fit
- Crew neck
- Raglan sleeves
- Minimal seams for chafe reduction
- Pique knit for increased moisture control at center back, arms and sides
Our Model
Our Model
- Model is 6'2.5" and wear size M
Fabric
Fabric
A very special blend of NASA-developed thermoregulating Outlast™ yarn and Tencel—a yarn made from sustainably-grown wood using a closed-loop system. The result is soft, durable, and moisture-managing.
- Breathable knit structure at center back to regulate sweat
- Ultra-stretch
- 46% Tencel, 41% Outlast™, 10% Nylon, 3% Spandex
- Machine wash and tumble dry

Mens's Size Guide
| Size | Chest | Waist | Hip |
|---|---|---|---|
| XS | 32″-34″ | 26″-28″ | 32″-34″ |
| S | 35″-37″ | 29″-31″ | 35″-37″ |
| M | 38″-40″ | 32″-34″ | 38″-40″ |
| L | 41″-43″ | 35″-37″ | 41″-43″ |
| XL | 44″-47″ | 38″-41″ | 44″-46″ |
| 2XL | 48″-51″ | 42″-45″ | 47″-50″ |
| 3XL | 52″-55″ | 46″-49″ | 51″-54″ |
| 4XL | 56″-59″ | 50″-53″ | 55″-58″ |
Still have questions? Speak to a Jaanuu fit specialist here
Free Shipping
Applicable to all $50+ U.S. orders.
Extended Returns
Orders placed from Nov 10 – Dec 16, 2025 can be returned through Jan 31, 2026.
For our complete shipping and returns policy, see here.
