DW SM904 Cymbal Stacker 4"

This is a stacker that only works with 8mm cymbal stands. It's the shorter 4" model, great for smaller bells, I think. For larger cymbals there's a 6" model available.

DW is always at the top of the price list, but also good quality. There are cheaper stackers in the Thomann web shop if you are looking for something that "just works". The dw, however, looks the coolest!