R3G133-RA01-03 Fan Blower, EC Centrifugal, 240 V, AC, 133 mm, 13 mm. RadiCal fans are one piece backward-curved impellers made of high-tech composite material. These centrifugals feature highly efficient GreenTech EC technology providing low-pressure solutions with backward-curved blades, used primarily as intake fans and do not require a scroll housing.