20-gauge CRS. Housing Flanges 18-gauge CRS, standard 4-piece construction, spotwelded to housing. White TGIC polyester powder coat 5-stage pre-treatment. Salt spray test 1,000 hours. Reflectance 92{04aef197e2a33ee94af7b49af44700ef917df47392523dfa0075c5fa9ebd8a96}. See Ordering Options for Antimicrobial Finish.