Cooking vessels at the extremes of size the very small and the very large occasionally raise issues. Because the auto detect feature that all induction units have is meant to assure that things from cooking implements (such as metal tongs or spoons or ladles) to jewelry (rings or bracelets) will not activate an element, the detectors are often set rather conservatively, so much so that on some units very small pots or pans will not be detected (the usual minimum pot base size for activation is from 4 to 5 inches, depending on particular unit.) But that is scarcely a major issue: if you really must have such a pot say a butter warmer there are accessories available that make it easy.