Ceia F12D Plate Top Refractory Plate. This is the Top Refractory Plate is for the Ceia F12 (OL-7012S) and it is for the F12 CEIA Induction Melter, plate is designed to hold the standerd F12 Crucible, has a 5-1/4" hole for a F12 Crucible (CN-611).