Tou
King Tou or Toi is the name of a king of Hamath, a city located in Syria. He is only mentioned in 2 Samuel 8:9-10 and 1 Chronicles 18:9-10.
Biblical text (KJV)
9 Now when Tou king of Hamath heard how David had smitten all the host of Hadarezer king of Zobah;
10 He sent Hadoram his son to king David, to enquire of his welfare, and to congratulate him, because he had fought against Hadarezer, and smitten him; (for Hadarezer had war with Tou;) and with him all manner of vessels of gold and silver and brass.
Source
Analysis
The text tells that King David successfully defeated an enemy of Tou's, Hadarezer, the king of Zobah. To congratulate David (and remind him that he was friendly to David), he sent his son Hadoram as an ambassador and with him a (presumably) large tribute, made mostly up of vessels of gold and silver and brass. David added them to the Temple treasury, after rededicating them.