Car seats with top tether

[villet]

Hi could someone pls recommend a baby car seat and a 4-12 years car seat that have top tether points as not all do

Neither of those types of car seat use top tether. It's generally only the harnessed stage for age approx 1-4 years which use top tether, and normally only the forward facing ones. (You can get rear facing/all stages seats with top tether but I wouldn't recommend any of them.)

Could you explain a bit more about why you're looking for this? I wonder if you've got mixed up with something else.

I have never heard of this. It wasn’t mentioned at the shop when I was looking for a car seat or in any of the online research I did so I don’t think it can be common.

Top tether is very common, it's just not usually used (at least in the UK) for the baby stage or the booster stage.

You know how isofix seats generally have a support leg? This helps reduce the amount that the seat tips forward in a crash, which is good because it helps reduce the strain on the child's body.

Top tether does the same job except instead of a solid brace against the car floor, it's an extra strap going over the back of the seat fixing it to the car. It's more common in the US and Australia so those places sing the praises of top tether but in Europe the same job is mostly done using support leg instead. And for the booster stage it's considered better to have neither.

For the 4-12 years car seat that doesn’t have support leg I’m surprised there’s no top tether in most car seats

It wouldn't have any function. The reason that you want to prevent the seat from tipping forward at that point is because the shoulder straps are attached to the seat at the top. But high backed booster seats don't have a 5 point harness, the child is restrained by the adult seatbelt. The seatbelt is already effectively "tethered" to the car at the top because the inertia reel will lock when the belt is yanked forwards. Tethering the booster seat itself would have no purpose and would just stop the head and body protection from moving forward with the child, so it could in theory even reduce protection e.g. from side impacts or a rollover. The little plastic shoulder belt guides on booster seats are not usually strong enough to contain the seatbelt during a crash and that is not their purpose anyway. They are there as what we call a "pre crash positioner" - to make sure it's in the right position for the child's shoulder.

Conversely in a seat with 5 point harness the harness very much should stay attached to the seat shell, so if you tether the seat shell back it helps keep the shoulders restrained too.