Can anybody recommend some good cool blocks

[MilaMae]

as we're doing 10 nights without ehu. I was wondering if those bigger/flatter???? blocks are better or is a block a block?

We have a monster Coleman box.
TIA

I don't know how blocks differ, but a big bottle (2l) of frozen water is better than any block. Unfortunately not many campsites will let you freeze them!

Big blocks do stay frozen longer, we always have one big and five small in the coolbox (and the other set in the freezer) when we change them over, the big one is always still pretty frozen and all the small ones just cold.