Multiple mailbox assemblies provide a sturdy, easy-to-use mounting platform for between two and four standard-sized outdoor post boxes. These products comply with all Federal Highway Administration (FHWA) and National Cooperative Highway Research Program 350 (NCHRP 350) regulations—including the mandated 42 inches of clearance between the ground and the bottom of each mailbox. Please note that assembly kits and additional post support hardware are sold separately.