GM269 Typhoon, the older brother of the GM257 Cyclone

Measurements in inch:
Base: 12.5" (inch)
Top: 12" (inch)
Diagonal: 18" (inch)
Center Depth: 4" (inch)
Mold Height: 5" (inch)

Always take your own kiln into consideration, but to use this mold in a "one and done" technique, as shown in the second image, refer to this tutorial for the Cyclone mold.