Note face in the center, which is similar to theA-33410knobbut with a markedly differentperimeter design.Knob diameter is 2 1/2 inches. Custom design for Daniel Burnham's Land Title & Trust Building in Philadelphia. The later adjacent annex building usedP-49240. Together below are the 2 1/4 and 2 1/2 sizes, details of the Corbin screwless attachment and the spindle used on the locks that allowed the exterior knob to be locked while the interior knob to operate.