Apollo A7LB Space Suit Helmet Disconnect Rings

Apollo A7LB space suit helmet disconnect rings, measuring approximately 11" in diameter: the larger ring is marked in white text, "Use with red helmet ring only," and is engraved on the opposite side, "PN-2904, SN-168"; the second ring is lined on the edge with 24 holes, and engraved with part numbers, "A7LB-109013-01, SN-1054, PN-2896." Manufactured by Air-Lock, these red anodized rings form incomplete suit-side neck ring hardware, including the outer shell for the helmet disconnect that would be attached onto the suit portion and mate with the red hardware at the base of the pressure helmet. The inner workings of the rings are not included. In overall fine condition.