The ones that go from 9 months/11kg to 11yrs are a type 1,2,3 carseat. They've very good (my two now have them), but I would hesitate to put a baby in one because they are more lightweight (read flimsy) that the Group 1,2 carseats that go up to 4 years. They are also far more upright, which is fine when your child rarely sleeps and has strong neck muscles, but not when it's head is likely to loll around asleep.
I would really recommend you always buy the best car-seat you can afford. There are lots of "up to 4yrs" carseats secondhand - just make certain that it's never been in an accident, dropped, or taken on a plane (baggage handlers will have dropped it!).