This square post mount is ideal for forklift mounting and consists of a 4" clamp base with a D size 2.25" ball. Attach any length D size socket arm, D size ball adapter and a device holder of your choosing for an ultra-rugged mounting solution for your forklift. While the base can support up to a maximum post width of 4", it can support any lesser width by rotating the base on the post, bringing the mounting bolts flush against the post.