These undies are made of cotton lycra jersey fabric, which has a lightweight feel, perfect for summer or year-round! All of my underwear have cotton crotches for added comfort and hygiene. Cotton jersey is made of 95% cotton and 5% spandex. It has a generous stretch, and most people find this underwear to be some of the most comfortable they have ever owned! Each pair of underwear I make is handmade to order. I painstakingly select fabrics that are bright, beautiful, and comfortable. I hope you see the difference! I wash all fabric in scent-free and dye-free detergent to preshrink and remove dyes from the manufacturer. The sizing on these tends to run true to size, but I do advise reviewing my size chart. No refunds or exchanges on underwear due to the personal nature of the product. Reach out to me if you have any questions, I'm happy to help! Pattern designed by the fabulously talented Stephanie Thiel of Rad Patterns.