For over a century Milton Brook of Stoke on Trent have been producing these fully vitrified porcelain and beech pestle and mortars. They are fired at controlled temperatures until the clays microscopic pores are eliminated. This gives a very low absorbency, very strong and dense product, which should minimize any risk of cross contamination. Still commonly used in the laboratory as well as the kitchen this is the definitive product of its type. In 4 sizes, size 0 or 5 fluid oz, size 1 or 7oz, size 2 or 1/2 pint, and size 3 or 3/4 pint.