GP Filter is one of the best selling activated carbon filter and is fast becoming the preferred choice for odor removal world wide, especially plant pollens and odors. The secret lies in the ultra light RC-48 carbon used inside every GP Filter. Odorous pollutants need only contact a GP filter for a fraction of a second to be totally eradicated from the air with 100% efficiency. This 24carat carbon source makes for the lightest, smallest and most effective carbon filters available with an average three-year life span. Our 100% virgin RC-48 carbon is activated in the largest carbon kiln in the southern hemisphere by Ti-West industries. Ti-West ensures every batch of RC-48 carbon is independently laboratory tested for purity and consistency to the highest available standards. The end result is 24 carat carbon (ASTM Guaranteed)