The Handy Post 1 sleeve (mailbox not included) is constructed of maintenance-free and durable PVC (Vinyl) and comes with a Lifetime Warranty against peeling, flaking, blistering, corroding, rotting, abnormal discoloration and manufacturing defects. It is designed to fit over an existing or new wood 4x4 (actual 3.5"x3.5") post, or can fit over many no-dig supports of similar dimensions. If your mailbox is secured to any type of wood 4x4 configuration, you can modify it by cutting it to a straight up 42" height or less to accept The Handy Post 1. The Handy Post 1 is designed to accommodate a single mailbox of any size, but looks the best with small (6.5"W) and medium (8.7") size mailboxes (see our Solo model for larger mailboxes). The cross arm is 8" across and 5" wide and will accommodate up to 75 lbs. This aesthetically pleasing, economical product will enhance any home, business or neighborhood property. The Handy Post 1 will add character to any setting. Conveniently packaged with stainless steel hardware and installation instructions included.