The 13" Round Ceramic Stone is the heat deflector for indirect (platesetter like) set-ups on the Large Spider, Adjustable Rig or Woo3. Ceramics are high temperature resistant cordierite formula. Dimensions are 13" round and 5/8" thick. Can be used as a pizza Stone above Big Green Egg's platesetter, atop the Adjustable Rig Extender or Woo3 Extender. 13.5" and 16" Round Stainless Drip Pans are recommended. Made in the USA.