I have seen a on other 107’s where there is a plastic turn knob on this threaded piece. There is a sticker there and I think it applies to the threaded area. I was wondering if someone could tell me for sure what this does when the knob is on it and I assume it can be tightened or loosened? I didn’t really know what to search for this to see if it had been posted before because I don’t actually know what it’s called. Any help would be appreciated. God bless you all and your families.