Plainsman Stoneware Clay - M340s $44.99 Sold Out This M340S is the same as M340 with added manganese to give a brown speckle in oxidation firing. This M340S is the same as M340 with added manganese to give a brown speckle in oxidation firing. Sold Out Added! You Might Also Like Plainsman Stoneware Clay - Coffee $74.99 Plainsman Stoneware Clay - M340 $44.99 Sold Out Smooth Red Stoneware Clay $49.99 Sold Out Plainsman Stoneware Clay - M390 $49.99 PHB Earthenware Clay $69.99
