I first heard a Zildjian swish knocker years ago on a Buddy Rich album. Around the same time I saw Buddy playing a 24” swish knocker with his big band. Simon Phillips used a 24” when I saw him with Toto. The 24” is not in production at the moment. I owned a 20” swish at one point. I remember playing it in a big band, riding lightly behind muted trumpets. That is a glorious and effervescent sound.