Estes Designs Mailbox and Streetscapes Adjustable Aluminum Trimmer Guard for 4x4 Mailbox Post: USA made, rust-free solution to protect posts Protects your mailbox post from rust and rot; covers old damage and prevents future damage Easy installation step-by-step instructions included Adjusts to fit varying post sizes (actual 4x4 post measurements vary slightly) Pre-drilled holes and durable .050 aluminum construction Made in the U.S.A. with mill finish