FULL 4x4 Heavy Duty Galvanized Post Cap (Inside Dimension is 4 in. x4 in.) Made of Heavy gauge galvanized metal; Measures 1-3/4 in. from top to bottom. Slips over a FULL-SIZE 4in. x4in. post (actual post cap size is 4 inch x 4 inch) 4 corners of post may need to be slightly sanded or notched with a standard box cutter in order for caps to fit on post. Maintenance Free and is able to weather all seasons Easy installation, just apply exterior caulk to the under-side of the post cap.