Phase Change Cooling Vests contain 6 oz. Flame resistant treated cotton. Soft to the touch. Lightweight, cool and comfortable. Flame Resistant through 50 washes. Meets ASTM F1506. Arc Rating 7.2 cal. NFPA 70E / HRC level 1 Embroidered Arc Rating Cools for 2-3 hours, set at 65\xC1 Spare cooling packs (PC-CPK) (Made in USA) Adjustable with hook & loop strap Vest Length 20 _\xEE Includes: Miracool Phase Change Cooling Pack Item # PC-CPK Cools up to 4 hours, set at 65 degrees Additional spare cooling packs for PC-VV & PC-VVFR Non-toxic Packaged in retail ready snap handle bag Made in the USA About Phase Change Materiel: Commonly used under military combat gear, hazardous materials suits, mascot costumes, and other apparel. Provide cooling comfort and heat stress protection in high temperature environments. Phase Change Material (PCM) releases long-lasting, temperature-specific 58F (14 degrees C), cooling relief. Phase Change Material (PCM) is 30% lighter than water. PCM is non-toxic, non-flammable, durable, reusable, lighter than water, and does not produce condensation. Benefits of Phase Change Cooling Vests: Heat Stress Protection Helps prevent exhaustion and dehydration Provides cooling comfort in high temperature environments Reliable and Reusable Trusted by US Military and Armed Forces Phase Change Vs. Evaporative Cooling: Phase change cooling provides a lower cooling temperature as compared to evaporative cooling products. The main difference is that evaporative cooling products are activated in water and use the evaporation process to provide cooling, and phase change products utilize freezable charge packs to provide the cooling effect. Phase change products typically get colder than evaporative items but do require re-freezing or extra charge packs for extended use. Occunomix MiraCool Value FR Phase Change Cooling Vest with HRC 1 Packs