A group 0+ seat, also known as a shell or a carrier, is a seat for children in the 0-13kg weight range. This is the first seat for newborn babies in which they can assume a naturally lying position. The construction of the seat is in the shape of a "shell", providing protection from all sides. Carriers are always mounted in a rearward-facing position and can be installed with car seat belts (which gives full versatility of installation) or a dedicated base with the ISOFIX system. Installing the carrier on the base makes it much easier and faster to put it in the vehicle, at the same time ensuring that the seat is properly secured. However, it should be remembered that cars have different inclination angles of the back seat and not every seat will be positioned in the same correct way in every car. The angle of the seat has a direct influence on the position of the child inside the carrier and the correctness of the position.