Sometimes happens events when screwed tube on Amphibia case becomes too worned out (exactly the threaded connection).
Inside screwed tube of Amphiba case there is rubber gasket (that gives protection of coming water inside case during winding or setting time actions , this rubber gasket is covered with stainless steel cap (this "cap" fix rubber gasket on it's place).
Here is a completed set "screwed Amphibia's tube + rubber gasket and steel cap."
This item fit well to all modern and retro Vostok Amphibia cases.
Original Vostok Inc. produced item.
Favinov watch manufactory
USA STORE