Surface Mounting Collar - 6 Door High for Double Column 4C Mailbox - SM06DSurface Mount Collar 6 Door High for Double Column 4C Mailbox The Florence Surface Mount Collar is designed for 6 door high, double column USPS 4C mailboxes. It allows a 4C mailbox to be mounted directly onto a wall with no wall cut required, making it ideal for installations with limited wall depth. Constructed from heavy gauge aluminum, this USPS approved surface mount collar is easy to install and provides a sleek, finished appearance. Compatible