The CYBEX Eternis S with SensorSafe™ is the only seat your child will need from birth and beyond. With three modes - rear-facing, forward-facing, and booster, this All-In-One Convertible Car Seat is designed for use from birth up to 120 lbs. The Eternis S with SensorSafe features Linear Side-impact Protection, and a patented 3-position reclining headrest that guides the child’s head and neck into a proper position while they are asleep. With SensorSafe™ technology, you'll gain instant insight into your child's well-being—right to the SensorSafe app on your phone. Built into the chest clip of CYBEX car seats, SensorSafe provides alerts when unsafe situations arise including if a child unbuckles themselves; if the back seat has become too warm or too cold if a child has been seated for too long, and if the driver accidentally leaves the child behind.