[UK] What's the difference between these two Graco car seats

Hello, and sorry if i sound a bit daft.

Other than the way it 'looks' and the price tag i can't really see what the difference is.

What is the difference in the ways it matters? (i.e. safety, ease of use and logevity..)

One is LX the other one is R129.

https://www.amazon.co.uk/Graco-SlimFit-ISOCATCH-Connectors-Approx/dp/B0846HL7ZF?ref\_=ast\_sto\_dp

https://www.amazon.co.uk/Graco-Slimfit-Group-Birth-Approx/dp/B0BMGN89G3?ref\_=ast\_sto\_dp&th=1