Gorilla Carbon Filter 4"x12"More Effective & Longer Lasting: 80 90% of our coconut carbon structure is made up of micro pores, giving Gorilla Tactical Carbon Filters up to 50% more carbon surface area to bind and eliminate pollutants than common pellet filter alternatives. Optimized Design for Peak Performance: The longer odors and contaminants come in contact with activated carbon (commonly referred to as dwell time), the more effective they are at removing those contaminants