It made by stainless steel, We need wash more time, use Liquor and Spirits wash this flask^.^.TOP GRADE MATERIALS: These flasks by YWQ are made out of premium quality stainless steel, ensuring that your experience will remain the greatest year after year. Non toxic, antiûcorrosion and anti-rust product.A grip-friendly matte black flask of 8 oz, a funnel for easy use.