Interesting product. Kinda pricey for a piece of foam but it does take some of the harshness out of the cymbals for home/studio use without really changing the fundamental crash sound too much. These do hinder the cymbal swing some so for live may not be best depending on drummer preference. I like the 70mm best out of the 3 I've tried so far (60,70 and 80). These work well on crash cymbals but I don't recommend them on the ride because they work by dampening the sounds that come from the bell of the cymbal so if you use a lot of ride bell these kill that sound. I have not tried these on the hi hat as I don't see the need.Note that these are the moderator series which are new and different from the smaller diameter optimizer series foam cympads that replace the felts on top and bottom. With this product you mount in on a metal washer under the cymbal and then can still use a felt on top or an optimizer cympad on top.