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 comfort zone, maintaining the perfect temperature for your baby. The cleanwater tub grows with baby 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 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 tub to the adult tub to keep your growing baby secure and well positioned during bathtime (6+ months). The newborn insert and rinse cup are included.