The Probe Insulator socks are made of 0.5 mm. Metalite Titanium to ensure warm feet while only using thin fabric. 

Size Chart:

• XS shoe size 2 - 4  /  EU 33 - 35.5
• S shoe size 4 - 6  /  EU 35.5 - 38
• M shoe size 6 - 9  /  EU 38 - 42
• L shoe size  9 - 12  /  EU 42 - 46
• XL shoe size 12   /  EU 46