UGG boots are famously known for their use of high-quality sheepskin. The outer material is typically made from genuine sheepskin, which is known for its softness, durability, and warmth. The inside of UGG boots features a luxurious and cozy wool lining that provides excellent insulation and comfort. This combination allows the boots to effectively regulate temperature, keeping feet warm during cold conditions while remaining breathable in warmer weather. UGG takes pride in sourcing its sheepskin responsibly, ensuring that it meets specific quality standards. It is worth noting that the brand offers various models, and while many utilize sheepskin, other materials may be used in different styles. For specific product details, it may be helpful to check the descriptions on the most current product pages available on their website.