Thanks to its own R&D department, DUOFEN has an edge over others in developing exclusive designs upon customer drawings. Options of purchasing either AB grade or A grade are available. With mature management system and stable product quality, DUOFEN has passed the certification of ISO 9001:2008 international quality control system. Meanwhile, most basins of DUOFEN was CE approved.Basins of DUOFEN are made by applying white jade clay with Japanese crystal self-cleaning glaze, leading to a feature of durable strength and shiny surface.