Sterkowski Wool Petersham Traditional Ivy League Snapbill Flat Cap To measure your head size get a soft tape measure. Measure around your head above your ears and eyebrows where your hat would normally sit. If your head size falls between two sizes, we recommend that you choose the larger size of the two. If you like loose fit, then please adjust the soft measuring tape in a loose way. Warm, simple, sturdy Snapbill Lining Made with petersham: (76% wool, 14% nylon, 10% cashmere)