How to open UMIK to change gain

[pjug]

I can't seem to get this to budge. But I am trying to open it with tweezers. It is counter-clockwise to open it, right? Am I going to have to buy a spanner wrench to get it open?

 

[pjug]

Today I received this tool. The conical end fit nicely and opening the UMIK-1 was then a simple task. I guess the tool might be useful down the road if I can find it when I need it!

https://www.amazon.com/gp/product/B00J5F6ZI2/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

If you are lucky your UMIK-1 won't have the ring fastened so tightly that you need this.