The narrow slotted mounting base is used for the positioning of 0.5" dia. stainless steel posts and post holder assemblies. The post/post holder is attached to the base via a counterbored clearance hole with a ¼-20 socket screw. The base is held in place with another socket screw in the slot. The slot length allows the post to be centered at the mid-point laterally or at 45° on a 1" center hole breadboard. Anodized aluminum.