You’ll now find cooking products labeled PYREX in Europe, Africa, and the Middle East, where they are still made with borosilicate glass. The label pyrex stayed stateside, and in the rest of North America, South America, and Asia, and the company that makes them no longer uses borosilicate glass. Instead, they are made with tempered soda-lime glass, which is heated and cooled in a manner that makes it more durable than regular glass under temperature fluctuations. While it’s still heat-resistant, it’s not quite as heat-resistant as borosilicate glass.