The tea doesn't circulate much in the water. The affinity between the two jaws are often poor, and tea leaves often escape. Use in mugs and small kettles. Opening the jaws easily discards the leaves. Use in mugs and small kettles.
Larger versions exist for large kettles.
Leaves are easily discarded. Also, leaves dry fast in it. This make it possible to leave it for a day and then just discard then-dry leaves. The tea circulate freely in water. Larger versions exist that hold more water.