300 AAC BLACKOUT laser markings are on both sides of the ejection port cover. It will show when the ejection port cover is open or closed.
Ejection port cover is permanently marked on both side so 7.62 x 39 will show when cover is open or closed.
Double sided marking so 6.8 SPC is visible when ejection port cover is open or closed.
Laser marked Para Bellum on both sides so it will show when open or closed.
Permanently laser marked on both side so .204 Ruger shows when cover is open or closed.
Both side are permanently marked .223 REM so it will show when cover is open or closed.