Just did some research, you want this kind with the lock on 4 sides and a rubberized gasket: "Glasslock".
Square should be better than round.
These are 2 compartment, which sounds even better. This is the style you want:
Square should be better than round.
These are 2 compartment, which sounds even better. This is the style you want:
We got ours at Sam's Club.