Constructed of 16 gauge steel, 3100 series Free Standing Rotary Mail Centers are available in two (2) styles. ALUMINUM STYLE Free Standing Rotary Mail Centers (#3100) are designed to accommodate a combination of five (5) aluminum rack ladder system mailboxes and data distribution system boxes. BRASS STYLE Free Standing Rotary Mail Centers (#3150) are designed to accommodate a combination of two (2) brass or Americana rear loading mailbox units. Free Standing Rotary Mail Centers can receive mail from either the US POSTAL SERVICE or from a PRIVATE individual. Free Standing Rotary Mail Centers feature a vinyl finish available in five (5) contemporary colors.