Product review (3 stars): Good enough if you need it
If you have the misfortune to have a laundry without an outdoor vent for the dryer, you'll need something like this to catch the lint before it sprays into your apartment.  We have a condo unit in a high-rise building, and the laundry is in a small "closet" in the center of the unit, so we need this type of lint trap.

There are two problems.  One is that the design of the trap doesn't hold the internal deflector very well.  It's a small piece of plastic that deflects the air so it flows across the water in the trap, and you have to be very careful to position it on the too-small protrusions in the wall that hold it up.  If you're careful, it works OK and doesn't fall down.

The other problem is that it doesn't catch all the lint.  We were advised by someone else in the building to put cheesecloth over the deflector's vents so the lint can be caught before getting into the room.  That works, but you need to replace the cheesecloth after two or three cycles of the dryer.  Otherwise it will become clogged with lint and will impede the drying.