which is white on the top and bottom with black edges

Peened is the standard specification for any environment where users regularly have wet or soapy hands: shower compartments (per ADA §608

Wall Opening: 11 3/8" X 5 1/8" X 4 1/8" (290 X 130 X 105 mm)

the support posts are fashioned out of rectangular tubing that is 1 inch by 1/2 of an inch in size

24" Grab Bars | ASI 3701 Series (1-1/4" Diameter)

ASI 3801-12 (12 x 1.5) Commercial Grab Bar, 1-1/2" Diameter x 12" Length, Stainless Steel Capacity 1 L which is white on the12" Grab Bars ASI 3801 Series (1 1 2" Diameter) 12" (305 mm) length with 1 1 2" (38 mm) diameter tubing 18 gauge Type 304 stainless steel with architectural satin finish Concealed snap flange mounting cover snaps over flange to conceal screws Stainless steel flange continuously heliarc welded to tubing 3 1 8" (79 mm) O. D. flange (1 8" thick) with (2) #10 mounting holes 22 gauge stainless steel snap on cover, 3 3 16" (81 mm) diameter 1 1 2" (38 mm)