I bought a 2nd-hand Brita water pitcher that looks like that in the pic. It has a spinning plastic mechanism that mates with the cartridge. I have another Brita pitcher that is almost identical but it does not have the spinning mechanism. The pinning plastic bit block water when at rest. Water can only plass when a filter is inserted because a genuine “Brita”™ filter has a grooved cylinder that forces the plastic to spin ~45° and unblock the outlet.

The affordable generic Brita knock-off filters lack the grooved cylinder, so they are incompatible with one of my pitchers.

I’m not sure this is a crappy design. It seems to not be documented (according to my attempt at searching). Is there a sensible reason for having the spinning mechanism? It cannot be to fuck with the generic cartridge producers because it seems Brita abandoned that design themselves.