RFC Series cartridges are constructed with a 70-micronporous polyethylene outer shell and durable polypropylene end caps. The 2-3/4" OD cartridges have a polypropylene core and the 4-1/2"OD cartridges incorporate a spun polypropylene core. Sandwiched between the outer shell and the core is a bed of granular activated carbon(GAC). The unique radial flow design offers the benefits of granular activated carbon (GAC) filtration, such as low-pressure drop, while at the same time significantly reducing the release of carbon fines commonly associated with GAC style cartridges. RFC Series cartridges are available in a wide variety of sizes and are ideal point-of-entry (POE) and other high flow rate applications. * Based on manufacturer's internal testing. Model Dimensions Pressure Drop Filter Life RFC-BB 4-5/8"x9-3/4" 0.9 psi @ 2 GPM 35,000 Gallons Materials of Construction: Filter Media Granular Activated Carbon End Caps Polypropylene Outer Shell Polyethylene Inner Wrap/Core Polypropylene Temperature Rating 40F to 180F