The immersion heating coil is a simple device that uses electricity to heat water. Simply immerse it in a vessel filled with water, plug it in and the current flowing across the resistor warms the surrounding water. Although originating from the traditional cimarron tea ceremony (popular in the Mercosur / Mercosul countries) where maté tea was drunk from calabash gourds, the product has evolved since then to fit in with modern day lifestyles.