Bright nickle chrome plated. Meets UL 0.25 inch maximum spacing plug gage test. Steel wire rings 1.8mm (0.071")D., ribs 1.8mm(0.071")D., bright basic wire. Mechatronics, Inc. Metal Fan Guard Part Number: SGR-47 .xxx +/- 0.005 .xx +/- 0.02 ANG. +/- 1.5" For use on 119 mm. sq. fans RoHS Compliant