Sized to fit in the Caldera kiln, with a central opening to allow glass to flow. Made of vermiculite board. 11.5" x 11.5" x 1" (29.2 x 29.2 x 2.5 cm). Round hole diameter: 2.5" (64 mm).
Pre-fire before using. For more information about vermiculite products, including pre-firing instructions, see Tips for Using Vermiculite Board.