The insect-repellent treatment on these socks is based on geraniol, a plant-derived substance. It helps protect the wearer from insect and tick bites. The biodegradable agent is non-irritating to the skin and does not kill insectsReima clothing is always safe. It has a mild lemony scent. - 74% organic cotton, 16% polypropylene, 8% polyamide, 2% elastane - Sizes: - 3033 = EU sizes 3033 - 3437 = EU sizes 3437 - 3841 = EU sizes 3841 Machine wash at 40ºC, may shrink by 5%. Do not use bleach or fabric softeners. To best protect your child from ticks, tuck pant legs into the sock cuffs and keep the shirt hem inside the waistbandticks always move upward.