Which I suspect is doing Corning some brand damage. Pyrex(TM) used to be really tough low-expansion borosilicate glass, or perhaps properly tempered soda-lime glass, truly great stuff. Now outside of Europe and lab glassware it's non-tempered generic soda-lime glass, which is injuring quite a few people: http://www.consumeraffairs.com/news04/2008/08/pyrex.html