According to the description it should be 100% polyester but it feels more like cotton than anything else. It's not long enough to cover the tummy and given the fabric I'm sure it will sit down when washed. To return.
Hanes Sleeve T Shirt Large White Men's Clothing T-Shirts & Tanks: Premium Comfort and Versatile Style
33 Review
Men's XXL Super T Mockneck π from Lands End - Clothing, T-Shirts & Tanks
32 Review
AM Fitted T Shirt 3 Pack for Men's Clothing - T-Shirts & Tanks
46 Review
Next Level Premium Fitted N6210: High-Quality Men's Clothing & Essential T-Shirts + Tanks Collection
39 Review