I Solemnly Swear that I am up to No Good! Mischief Managed on Adult & Youth Cotton T-Shirt (in 26 colors) Genuine South Horizon product. Sold exclusively by South Horizon We ONLY use top Quality cotton t-shirts that last wash after wash. Fabric is Jersey Knit 100% Preshrunk Cotton Heather Grey is 90% cotton, 10% other fibers, Dark Heather is 50% cotton, 50% poly See sizes under PRODUCT DESCRIPTION below.