6x6 Post Cap - (Nominal) White Flat Top - 10 Year Warranty Fits a Standard (Nominal) post. (5.5" x 5.5" up to 5.75" X 5.75") 10 year guarantee against fading, discoloration and warping! These caps slide down the post 1.5" and are 7.5" at their widest point. High impact, remarkably sturdy ASA resin. The same material used to in automobiles! Quick and easy patented SNAP-CAP installation, built right into the cap!