Use this 43″ in-ground post to mount any curbside Mail Boss locking mailbox. The in ground post should be buried approximately 12 inches in ground in order for the incoming mail slot of the Mail Boss mailboxes to be within usps specifications of 41″-45″ above the road side surface. This post will fit securely over a treated wooden 4″x4″ post for deep installations and reinforcement with rebar stakes. The Mail Boss 7123 In-Ground Steel Post is a durable and secure mounting solution designed for installing Mail Boss curbside locking mailboxes. Constructed from heavy-duty galvanized steel and finished with a weather-resistant bronze powder coating, this in-ground post provides excellent strength, stability, and long-lasting outdoor performance. The post is designed for in-ground installation and can also be used as a sleeve over a treated 4x4 wooden post for additional support. It includes mounting hardware for easy installation and offers a clean, professional appearance for residential mailbox setups.