Food-grade stainless steel
Food-grade stainless steel is a material that is specially designed to be safe for the cooking of various types of foods (or in this case, the boiling of water for hot drinks) and which is resistant to the wear and tear normally associated with this. This means that no matter how often you have a cup of tea, or any hot drink, you can be sure that the water you use will be of the safest possible standard, and that the kettle itself will be able to withstand constant high heats and everything that goes along with daily use in the kitchen.