I use this shock mount for the ST51 which it is also specifically produced for, not just the 55 and 66. I use it for my home recording studio and the mount holds the microphone very securely! people bump into it and it does its job. If you have one of those sterling condenser mics I suggest purchasing this shock mount
I've owned this shock-mount for just under 2 months, and has already stripped out. it never seemed sturdy since the day I received it, and am displeased with the design for that matter. However, while recording, it does it's job cutting out the low frequencies from jolts etc.