The PAD+ is an additional feature to improve comfort and safety, and should always be used with the iZi Flex FIX i-Size. One PAD+ is comes with the seat, and must be positioned on the vehicle´s shoulder belt. Comfort is improved by positioning a soft pad between the neck and the sharp edge of the shoulder belt. Safety is improved by positioning a soft pad between the chin and the chest to ‘soften’ the impact of the chin on the chest during a frontal impact. If you move the iZi Flex FIX i-Size from one vehicle to another, or from one side of the car to the other, you must also move the PAD+ with the seat.