The booties come in two sizes, making them suitable from when the baby is little. They are perfect for use in strollers, baby carriers, and car seats. For children who cannot walk yet, it is good with extra protection on their feets. The booties consists of natural and quality-assured materials. The booties are filled with wool, ensuring a comfortable temperature and keeping the child dry. The wool is temperature-regulating and keeps your baby's feet warm. The outer fabric is windproof, and has a water column of minimum 8000 and coated with BIONIC-FINISH®ECO which means that it's water repellant. All the materials in Voksi Booties are OEKO-TEX®standard 100, class 1 certified, which is a quality label that indicates that none of the materials in the product contain harmful chemicals. The booties have a good fit, ensuring they stay good on the foot. They are easy to put on and take off with velcro. Mix and match the colors with the Voksi sleeping bags and stroller mittens. Outer - 100% nylon Inner - 100% polyester Filling under - 100% wool Wash at 40°C wool program, use wool detergent. Do not bleach, and tumble dry at low heat with dryer balls until completely dry.