Perforated Face Diffusers UL Listed for T-bar lay in applications. Round neck and square neck perforated ceiling diffusers with face mounted adjustable pattern controller and UL-Listed ceiling radiation damper. XG-7500-FRS / 7550-FRS Series Perforated ceiling diffuser with a UL-Listed ceiling radiation damper. VIEW XG-7500-FRS / 7550-FRS Series https://catalog-api.greenheck.com/api/category/en-us/604 XG-7600-FRS / 7650-FRS Series Perforated ceiling diffuser with radiation damper. VIEW XG-7600-FRS / 7650-FRS Series https://catalog-api.greenheck.com/api/category/en-us/605 XG-SPRTB-FRS Series Perforated non-ducted scree with a UL-Listed ceiling radiation damper. VIEW XG-SPRTB-FRS Series https://catalog-api.greenheck.com/api/category/en-us/606