Also known as borosilicate glass, Pyrex does not crack under pressure or when exposed to extreme hot or cold. By this token, borosilicate glass is the only ISO certified material for sex toys. This type of glass dildo is also extremely durable and easily withstands wear and tear.
Example of a glass dildo. Pictured: Glas 8" Glass Ribbed G-Spot.
Glass dildos also have the added advantage of being odor resistant.
They are also known to intensify orgasms since they are more rigid and smooth than other types of materials. In fact, sex experts often recommend glass dildos for direct G-spot stimulation. More importantly, couples can choose to heat up or cool the dildo in the freezer since glass automatically absorbs the temperature to which it is exposed.
Glass dildos are hypoallergenic. They are an ideal choice for individuals who suffer from sensitivity or allergies to some materials.