Made of foot-shaped silicone with non-slip processing. - Color: Pink - Design: Footprint - Material: Silicone - Back: Non-slip processing The black spots on the bottom are not mold. Previously, a brow pencil broke and I stepped on it without realizing it while concentrating on exercise. I washed it thoroughly afterwards, but some marks remain. However, the black marks will not transfer to other items (such as yoga mats), so you can use it with confidence. Thank you for looking!