Craghoppers has changed the active ingredient in their insect-repellent clothing: they now use plant-based eucalyptus citriodora oil (biocide) as the active ingredient. It is milder than previously used active ingredients but helps prevent insects from landing and staying on the fabric surface. Socks suitable for everyday wear and hiking! - Heel and toe cushion - Package contains two pairs of socks The active ingredient complies with the European Biocidal Products Regulation 528/2012/EU. It is certified at level 1 by ZDHC (Zero Discharge of Hazardous Chemicals), and the manufacturer is seeking certification at level 3.