【UPGRADE】Compared with the earlier 97011790 grille wall fan kit, we have upgraded the materials of parts such as the screws and the built-in threads of the knobs. We've replaced the original plastic threads and iron screws with those made of pure copper and stainless steel. Moreover, with the adoption of modern hardening and heat treatment processes, the service life of our product far exceeds that of the original one PLEASE NOTE that there is A SMALL HOLE at the top right of this grille for installing the control knob, so if your current grille does not have such a small hole, it may not be suitable. Before purchasing, be sure to remove the old grille and measure its dimensions to avoid any mismatches. If you have any questions, please contact us promptly via Amazon, and we will reply to you as soon as possible. The grille size is：11 1/2 inch x 11 1/2 inch，OEM size and color，Please confirm your model and size before purchasing. The grille looks similar, but the size or model is different 97011790 Grille (Replaces Old Style) Compatible Models:509S Ventilation Fan，509S-A Through Wall Fan - 180 Cfm / 6.5 Sones，509S-B Through Wall Fan - 180 Cfm / 6.5 Sones，509SMG ，503，505，507，509S (replacement old style) We have treated the surface of the exhaust fan cover to make it more textured and easy to clean! bathroom exhaust fan cover exhaust fan cover replacement parts bathroom fan cover bathroom vent fan cover replacement parts bathroom exhaust fan cover bathroom fan， Replacement for Nutone Broan Grille : Through wall ventilation fans replace 97011790 S97011790 509S-A 509S-B 509SMG 503 505 507 509S (replacement old style)