Military dog tags with silencers. Silencers are rubber rings that cover the outer edge of the tags to keep them from clanging together.
狗牌
air force、army、bookami clip art、dog tag、marines、military、navy、necklace、seal、special forces、tags、volunteer
空軍、軍隊、剪貼畫書、狗牌、海軍陸戰隊、軍事、海軍、項鍊、密封、特種部隊、標籤、志願者
資料來源：openclipart ( https://openclipart.org/ )