The hands free way to carry child car seats. With the introduction of Pac Back, people traveling with young children can now carry a bulky car or booster seat while keeping both Hands Free. The lightweight Pac back was designed in reponse to the new recommendations from the FAA and by all major airlines. They suggest children who weigh from 20 to 40 lbs be placed in a car restraint system such as an approved car or booster seat.