The britax first class plus car seat is a combination car seat that can be used first as a rearward facing seat from birth to 13kg44 then as your child gets older a forward facing seat up until around 4 years the first class can be used in multiple cars as it has a slim base and 2 seat belt routing options that have a better fit in many cars it is also lightweight and installs with the 3 point belt making it universal for most cars once installed the spring loaded belt mechanism ensures a