Thank you Bill for posting, I hope this call serves you well, and thank you for the kind words. I have always had a fascination with the calls made for hunting by Charles Jordan and Simon Everitt. The Simon Everitt call utilized a thread spool which could be used to protect the wing bone section of the call when taken apart and plugged into the barrel.The thread spool could also be plugged into the barrel (with the midsection and wing bone mouth piece assembled,) to effectively mute the call for softer calling. Yes, you can mute a call with hand placement,but the Ivory (spool) changes the harmonics and volume, in my opinion, and was a successful experiment.