AIUI, products with "PYREX" (all-upper) is the old/original product, and "pyrex" (all-lower) is the new stuff: * https://www.allrecipes.com/article/what-is-the

AIUI, products with "PYREX" (all-upper) is the old/original product, and "pyrex" (all-lower) is the new stuff: * https://www.allrecipes.com/article/what-is-the-difference-between-two-pyrex-types/ https://www.allrecipes.com/article/what-is-the-difference-be...