AC Fans /DC Fans /Blowers /WireFanGuards /PlasticFanGuards /FanPowerCords /FanFilters Wire Form Fan Guards Back Part Number: TWG-123 For use with fan size Rib Material Dia. Ring Material Dia. Mounting Hole Centers (M/C) Outside Ring Dia (OD) mm in mm in mm in mm in mm in 120 4 1/2 1.60 .063 1.60 .063 104.8 4.13 109.5 4.31