Tub Dry is a function available in some washing machines that helps to remove any remaining water drops in the wash tub or spin basket after the wash cycle is complete. This function is used to prevent mold from growing in the washing machine. The Tub Dry cycle works by spinning the drum at high speed to remove any remaining water drops. The duration of the cycle may vary depending on the washing machine model and manufacturer. The Tub Dry function is different from the Air Dry function, which is used to dry clothes by blowing hot air into the drum after the wash cycle is complete.