The Yoshikawa kettle line-up uses 18-8 stainless steel, which is both durable and corrosion-resistant, for the main body and special steel developed in Japan for the base in order to ensure ease of use, and all elements, from design through to production, represent “Made in Japan” levels of quality. They have been awarded the SG Mark, which is one of Japan 's safety standards, and this ensures that they can be used safely and without anxiety on induction heaters and all other types of heat sources. Safety is guaranteed without having to consider housing conditions or other usage environments.