I already reviewed the 6"
This is the 4".
To be used by me to put on bottom cymbals that are not played on the cup (because it will require some precise play to reach the cup with this short stacker), and are at least 4" bigger than the top cymbal.
Very nice tool to expand a kit within it's footprint.
But in some setups with much vibrations, they will turn loose after a while. They won't fall off immediately. You'll see them jiggle a little.
But a drummer should know to tighten some of his hardware regularly.