Australian milled 100% cotton jersey knit neck tube with our polymer cooling gel caps around the lower third of the tube. Once activated gel will stay cool for hours. Rinse in cool water and ice or refridgerate for a few minutes to reactivate coolness. Machine wash in cold water and hang out in shade to dry. Cooling gel will crystalise after drying garment out thoroughly. To reactivate just place in a bowl of cool water then refridgerate. We have been making cooling garments for over twenty years here in our workshops after their conception for a group of workers out near Marble Bar in Western Australia. Boiling hot, the middle of summer and our idea worked.