This Ocuisine roaster is made from borosilicate glass - a guarantee of strength and quality. The tempered glass is extra resistant to thermal shock, being able withstand extremes of temperatures of -40°C to +300°C, so it can be used both in a very hot oven and in the freezer. (Not for use on the hob). OCuisine is manufactured by International Cookware, who also make Pyrex