Silicon Carbide Sagger tray.
Outside Dimensions: 5.9" x 5.9" x 2.75" (150x150x70mm)
Inside Dimensions: 5.4" x 5.4" x 2.5" (137x137x63mm)
Can be used for roasting ores and metallurgical products and other furnace tasks. Ideal as a crucible spill tray.
Crucibles shown in images sold separately.
Sometimes called a "Saggar"