It refers to the wood ass the material ,with a piece of patchwork glue spliced together into a round bucket-shaped water container.Because of its good insulation effect ,in the bathroom industry is mainly used for storage of hot water ,in order to provide a container for soaking feet,its wood mainly to choose about 20 years of age of cedar wood ss the base material splicing,in order to achieve sealing water leakage ,keep the water temperature slowly falling effect ,do not need to have been adding hot water to keep the watertemperature.