Respironics dreamstation disposable ultra-fine filter is a white filter (with integrated light blue carrier) and is designed for use with all dreamstation series cpap/bipap machines. this filter is disposable and should be changed regularly when soiled. the filter provides filtration that may enhance comfort without increasing noise or changes in efficacy. ultra fine filters from philips respironics are an optional accessory for increased filtration efficiency. this filter is necessary for those who live in a home with great amount of dust and those who live with pets. the ultra-fine filter will ensure that the air you are breathing throughout your therapy is dust free as possible.