A "thread protector" is a device used to protect the threads on the ends of pipes, tubes, or other threaded connections from damage during storage, transportation, or handling. Thread protectors are typically made of plastic, steel, or other durable materials and are designed to prevent dirt, debris, moisture, or other contaminants from entering and damaging the threaded connections. They are commonly used in the oil and gas industry to ensure the integrity of threaded connections and prevent costly damage or leaks.