Edgun R5M Super CHEAP/EASY Fix to the "Puff of Air to the Face"

I just checked the link above and did not see the breach oring size listed under the lelya section. I measured the breach oring in my .25 cal and it appears to have an inside diameter of 6mm, and a cross section of 2mm. Hoping someone can confirm its a 6X2 ?

Yep.

1556670514_18816559405cc8e8329214f3.15546862_4A1E8081-F7E3-4D00-B956-5EC65EF6335A.jpeg