DUNDER MIFFLIN PAPER COMPANY on Long Sleeve Adult & Youth Cotton T-Shirt (in 23 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 Ash Grey is 99% cotton, 1% other; Heather Grey is 90/10 See sizes under PRODUCT DESCRIPTION below.