gas washing bottles with SECURITY SINTERED DISC use

hello,

I make a fast look at the "new" gas washing bottles, finally!

some have a ceramic "stopper" in the lower mouth with porosity 0, 1, 2. This is the same with SECURITY SINTERED DISC?

porosity 0 for what? and 1, and 2??? this scale is more a personal choice or for security reasons or...???

diferences with the classic open tube?? I think the porosity is for gas best dissolution, right? but how to clean a porous porcelain disk?

where I can find one of this?

https://www.labrotator.com/?product=gas-waschflasche-150-ml-...

this is an advanced concept in GWB???

I love sting punk and comunist glassware!!!