Made with U. S. 37. 5 Polyester Technology, the Jackson 2. 0 is sourced and made entirely in the U. S. 37. 5 Polyester helps your feet stay in their natural comfort zone by helping you cool when it's hot and warm when it's cold. Reinforced construction and low-stress seam placement reduce wear and tear, increasing the life of the sock. Advanced knitting techniques create a seamless toe closure in the toe box, reducing bulk and eliminating blister-generating friction.