Fair enough.They are not tiles inset in to the cover they are concrete block pavers so as John says it will be heavy
I used the word 'tile' fairly loosely. I don't know whether they are things one can buy, or whether someone created them by slicing up pavers, but the 'things' on top of my neighbour's cover are clearly much thinner than the surrounding pavers. It is fairly heavy but, as I said, even in my 'old age' I can still lift it (I did quite recently)