This set of two dog tags come with chains.  The first dog tag is engraved with "Toxic Water Survivor with the US Flag/Skull flanked the the Biohazard Symbols."  The second dog tag is engraved with "(Rank, Name and Toxic Exposure dates.)"
 
Each dog tag is about 50 x 29 x 1 mm/ 2 x 1.1 x 0.04 inches, and the round hole of the disc is approx. 3 mm/ 0.1 inch in diameter. They are sturdy and reliable, not easy to break or fade, and lightweight for wearing.