AQUAPRO SILVER IMPREGNATED GRANULATED ACTIVATED CARBON WATER FILTER CARTRIDGE 20 inch x 4.5 inch 5 micron Silver GAC (Granular Activated Carbon) is made from organic materials such as wood, coconut shell and coal and is impregnated with silver. It is an effective adsorbent because it is a highly porous material with a large surface area to which contaminants may adsorb. The construction of the cartridge allows water to enter at one end and pass through the entire length of the carbon bed before exiting the other end of the cartridge. Pre and post filters pads reduce carbon fines and sediment from entering the water. Unlike standard GAC filters, silver carbon inhibits the bacterial growth in the fine cracks of the activated carbon to ensure the carbon stays effective for taste, odour and colour reduction in un-chlorinated water. Ideal for Rain Water.These Cartridges are refillable and reusable. Specifications: 20 Inch x 4.5 Inch 5 Micron Maximum temperature 125F / 52C Maximum Operating Pressure: 17kg/CM² (Approx 242 PSI)