... ") RO System Parts! CTO Water Filter Cartridge---Block Activated Carbon Filter filter cartridge,filter core,water filter cartridge,CTO 20 ... ,filter core,water filter cartridge,CTOThe carbon filter cartridge is made up of the granular carbon media and the food grade housing ... Length:10.20inchCTO cartridge, can be made of normal carbon, or coconut carbon, has different color, you can choose by yourself. ...