We finally found it!  We had quite a few requirements for a loose-leaf tea diffuser that we just couldn't seem to get met until we finally found this one!  This is what we were looking for and how it will help you make that perfect cup of tea:
 
-Easy to open and clean
-Submerges: Will sink, not float, when water is added
-Easy to remove from the cup after steeping
-Still able to add a saucer on top of the tea while steeping
-Not plastic or silicone
-Quality made so it won't break after a few uses