Our physiological babycarrier: From 3.5 kg to 20 kg Front, Hip & Back Carry. - Open in summer, closed in winter. The ventilation window on your baby's back keeps him cool and allows you to check his posture at a glance. Its window adapts to every climate. - The PhysioCarrier 2 is designed to respect the natural hip spacing of your newborn baby thanks to its width-adjustable seat. The narrowest in its category (11cm). In just 10 seconds, adjust the width and height of the baby carrier to your child's unique shape.