Nuvo Iron Decorative Pyramid Aluminium Post Cap for 5.5" x 5.5" Posts - Black PYRAMID POST CAP - Nuvo Iron black aluminum cap for fence posts. ORNAMENTAL - Top the perfect fence with stunning ornamental black aluminum for a classy look. PROTECTION - Marine grade architectural designed alumni post caps add value and protect top of posts. FOR FLAT TOP POSTS - Fits standard 5-1/2"x 5-1/2" planed posts. Cap fits over the post around 0.7". DIMENSIONS - Square post cap: 6 x 6 x 1.75.