Lingyu is famous brand of compressed air dryer and filter in China. A moisture filter is a device that removes moisture from the compressed air before it is used. It is typically placed between the compressor and the tool or equipment that uses the compressed air. The filter works by passing the air through a desiccant material, which absorbs the moisture and other contaminants. The filtered air is then released for use, while the moisture and other contaminants are trapped in the filter.