KDF is a specialized purification media that removes heavy metals and makes the purification cartridge bateriostatic GAC is also commonly used for the improvement of taste, colour and odour. Our premium KDF/GAC cartridges contain 40-50% KDF (by weight) which is more than most KDF cartridges from other manufacturers, offering you the best value and quality and ensuring that your water system is optimally effective. What's in the box 1x 10 inch slimline (10x2.5" size) Premium GAC/KDF Filter