The Handy Post for 3 sleeve (mailboxes not included) is constructed of maintenance-free and durable PVC (Vinyl) and comes with a Lifetime Warranty against peeling, flaking, blistering, corroding, rotting 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 mailboxes are 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 for 3. The Handy Post for 3 is designed to accommodate two mailboxes of any size or three small (T1) or medium (T2) mailboxes on one post. Note: It is not designed to hold three large or extra large mailboxes, which are typically 11+ inches each in width (see our 3XL model). The cross arm is 31" across and 5" wide and will accommodate up to 50lbs. This aesthetically pleasing, economical product will enhance any home, business or neighborhood property. The Handy Post for 3 will add character to any setting. Conveniently packaged with stainless steel hardware and installation instructions included.