DESC: The Safety 1st Intera 4-in-1 Convertible Car Seat will take a child home from the hospital, take them to their first day of school and even to their wedding! OK, maybe not their wedding, but this convertible car seat certainly spans several years. With most car seat laws requiring a child to stay in a car seat until 8 years old or about 100 lbs., getting value out of a baby car seat is very important. This Safety 1st car seat works rear facing from 5 lbs. and to 100 lbs. as a booster.