Ejection port dust cover is permanently marked .22 LR (.22 Long Rifle) on both sides
so it is visible in open or closed position.
Mark your upper to designate the caliber with using a single lower with different uppers.
Fits AR-15/M4 Upper Receivers.
Laser EngravedMade In USA.
May occasionally have some variation in laser work.
Dust covers are true mil-spec and arrived to us in bulk bags of 500 each and coated with lubricant.