These scholl pedi refills with marine minerals are designed to fit allscholl foot files the wet and dry roller heads will soften and smooth regular hard skin to give you soft and beautiful feet effortlesslyits recommended that you only use scholl roller heads with scholl electronic foot files and replace every 3 months for ideal efficacy you can remove hard skin with this roller head on wet soaked or dry feet for use in under water use only in a waterproof foot file eg the scholl rech