The way this one is designed, it has 2 "tongs" in the back and 2 "tongs" in the front with 2 small tabs about 2/3 of the way down. The back tongs lock into the filter keeping it from going side to side, and the 2 tabs lock the fliter in place preventing it from pulling out when you are pressure washing it.
The front tongs hold the filter against the back tongs.
Then it is counterbalanced in the back so that when you set the filter in place, it doesn't topple over.
Simple, no moving parts, nothing to break, sturdy, easy to use and clean.