Borosilicate glass is one of the safest materials. Extremely resistant to breaking, dishwasher safe and compatible with any lubricant. You can freeze or boil the toy to then use in temperature play! Non-porous, hypoallergenic, phthalate & latex free. These toys are hand-made, so they may have very slightly different dimensions, hues and shapes to those shown. Shipped with a padded, plush storage pouch.