Concealed mounting flanges: 18-8, type-304, 1/8" thick, stainless steel plate; end flanges 2" x 3 1/8" with two holes for attachment to wall. Intermediate flanges 2 5/8" x 3 1/8" wide x 3 1/8" diameter. Snap flange covers: 18-8, type-304, 22-gauge drawn stainless steel with satin-finish. 3 1/4" diameter x 5/8" deep, each cover snaps over mounting flange to conceal mounting screws.