Question about Eros Tube Covers

[bladerunner80]

Hi all, just wrapped up my Eros 2 build last night (past all resistance and voltage checks, super stoked!).  Man, what a fun kit to build!  Anyhow, had a quick question about the tubes.  What are the metal cylindrical covers for the EF86 and 6922 tubes? I have a few tube amps from Schiit and a Bottlehead Crack, but have never seen these used on other tube amps.  Just curious, thanks!   

 

[Paul Birkeland]

These are shields that are somewhat helpful in reducing the pickup of external noise.