SDPK0000 BLACK DRIVE-IN POST KIT | The Steel Drive-In Post is a popular choice for just about any mailbox installation. With its clean and compact design, the post will also greatly enhance the look of any property. The rust-resistant steel post and cross arm feature a black powder-coated finish that offers the utmost in durability and good looks. The post can be installed directly in the ground without the need for digging, while the cross arm is adjustable.