be careful when deciding on how you will be using your car-seats. infants shouldn't be in car-seats continually for more than an hour at a time at the MOST. oxygen levels can dip pretty low if there not taken out and allowed to recover there o2 levels. Don't get me wrong car-seats are necessary and every one should learn how to use the correctly IN CARS. car seats are for cars period. (if you want to learn more google positional asphyxia and car-seats)