The ultra-lightweight premium Stretch Knit fabric is our lightest weight cooling towel even when wet! It has a fine knit texture with no seaming for optimal comfort. The On-the-Go sizing is smaller for easier portability. When activated with water it cools to 30 degrees below average body temperature in under 30 seconds. Activate quickly in 3 steps: Wet it wring it out and Snap it.t stays cool for up to 2 hours so that you can comfortably stay active longer. To reactivate just re-wet and snap.