Only Thorlo have the technical background and medical research spanning 25 years to produce genuine performance outdoor socks. All fibres used in socks have strengths & weaknesses. No single fibre can offer performance in all. Thorlo’s blend of fibres provide the most suitable sock for each activity. No other sock brand is able to vary the padding density underfoot to give critical support under the arch and shock absorption at the toe & heel. Thorlo’s are graded by level of protection offered in the padding. From level 1 for performance in lighter weight footwear to level 3 for unrivalled performance & comfort in extreme conditions.