AC Fans /DC Fans /Blowers /WireFanGuards /PlasticFanGuards /FanPowerCords /FanFilters Wire Form Fan Guards Back Part Number: TWG-40 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 40 1.5 1.60 .063 1.60 .063 32.0 1.26 29.1 1.15