The tumble dry symbol is a square with a circle inside it. If the circle is empty, it means the item can be tumble dried on any heat. If there is one dot inside the circle, it means the item should be tumble dried on low heat. Two dots inside the circle indicate that the item should be tumble dried on medium heat. If the circle inside the square is crossed out, it means the item should not be tumble dried. Instead, the item should be air-dried or drip-dried. It is important to follow the care label instructions to avoid damaging the item during the drying process.