The 4moms® Cleanwater Tub features a unique design which provides a constant flow of clean water. The clean water reservoir holds fresh water for rinsing while dirty water flows out of the side drain. The built-in color-coded digital thermometer helps you identify a comfort zone, maintaining the perfect temperature for your baby. The Cleanwater Bath Tub grows with your infant in 3 stages, making it the only tub you will ever need. Stage 1: Newborn - use the newborn insert included to ensure a snug and secure fit for smaller babies (0-3 months; up to 15lbs); Stage 2: Infant - remove the newborn bath tub insert for a more comfortable fit as baby gets bigger (3-6 months or until baby can sit up unassisted); Stage 3: Older Babies - once baby begins to sit up, move the cleanwater baby bath tub to the adult tub to keep your growing baby secure and well positioned during bathtime (6+ months). The newborn bathtub insert and rinse cup are included. 4moms does not support the use of any third party accessories, as they have not been tested by 4moms and could pose a potential safety risk. Only use accessories manufactured and sold directly by 4moms.