This Jersey/Jacket is actually 40 percent wool, 30 percent polypropolene, 20 percent acrylic, 10 percent polyester. Since "wool" cycling jerseys tend to be 1/2 size or a full size small, best to order a size larger than you normally wear in a standard jersey. I normally wear a M, but found that a size L fit perfectly. The only reason I did not give the product 5 stars, was because the current advertisement indicates that it is a 100 percent wool jersey. No mention that it is a blend.