Shark Wood & Hard Floor Cleaner Concentrate 28 Oz. Italian Citrus USED WITH SONIC DUO SYSTEM, Material Feature Non-Toxic Item Volume 28 Fluid Ounces Concentrated solution adds value; 1 bottle concentrate = 7 refills Non-Streak Formula with No Dulling Residue Shark's Wood & Hard Floor Cleaner is designed exclusively for use with the Sonic Duo This Wood & Hard Floor Cleaner outperforms the competition and never leaves behind a dulling residue or streaky finish.