I thought all car seats fastened via base units that were attached to teh car via seat belts. Now I'm noticing that there are some that are buckled in directly, without a base.

Does anyone know what's safer? Or where I can find out?

thanks!

these carseats are called isofix,
your car also needs to have isofic fitting ( which most new cars have ) and the seat attatches directly to the car,
we have one and its fantastic, really tight and doesn't move atall
we also have the ones that go in with the seat belt and they are seccure and fit in my car but i prefer the isofic, really easy to put in and once they are in they are in
halfords or mothercae would be able to help you on this xx
hth

Thanks!