Pyrex glass is the most popular brand name for borosilicate glass. It is a common material used in glass sex toys such as dildos and butt plugs. Pyrex glass is very strong. It is resistant to cracking or breaking. Pyrex glass heats up and cools down quickly making it great for (careful) temperature play.
The main constituents in borosilicate glass are boron trioxide and silica. Items made from borosilicate glass are less susceptible to thermal shock than other glass items due to its low coefficients of thermal expansion.
More About Pyrex Glass
Consumers frequently find glass sex toys frightening due to the fear that they will break, but pyrex glass is incredibly sturdy.
Often, consumers and sex educators will refer to glass sex toys as being made of pyrex glass even though that is the brand name and not the name of the actual material.
