4x4 Heavy Duty Solid Aluminum Post Cap (Measures 3-1/2 in. x 3-1/2 in.) Made of Heavy Gauge Solid Aluminum, .04 inch thick Slips over a nominal 4x4 post (Actual size is 3-1/2 in. x 3-1/2 in.) Measures 1-3/4 inch tall. Ideal to complete a variety of fencing projects in extreme weather. Maintenance Free and is able to weather all seasons. Will change to green patina over time. Easy installation, just apply exterior caulk to the under-side of the post cap.