The Rooftop 360 Grease Containment System is revolutionizing the rooftop system market. Simple expandable "Flex Frame" design fits fan curbs ranging from 16"- 41" in diameter. System provides 12" of rooftop surface protection around the fan curb. System installs easily (approx. 1 hour). Kit comes complete with 8 - 12" X 58" filters and all components needed to install. Filter media -5 layer design Top - Pre-Filter Disbursement Layer Made Of Fire Retardant Material (FMVSS 302) Holds Grease And Serves As A UV Protectant Middle - Quadruple Heavy Duty Oil Only Absorbing Layers Made From Fire Retardant (FMVSS 302) Material WARNING : This product can expose you to chemicals including Cobalt Metal Powder and 1,3,5-Triglycidyl-s-triazinetrione, which is known to the State of California to cause cancer. For more information, go to www.P65Warnings.ca.gov .