The standard information for dog tags is as follows:

LAST NAME
FIRST NAME AND MIDDLE INITIAL
SOCIAL SECURITY NUMBER
BLOOD TYPE
RELIGIOUS PREFERENCE

For children's tags, customers often replace the SS# with the home phone number and many customers put the child's home address in place of the last two lines. In 1940, some dog tags were marked in the following manner: 1st Line - soldier's full name, 2nd Line - his full seven or eight digit service number and date of any Tetanus injections (e.g., "T42" or "T41 42"); an initial to indicate blood group. 3rd to 5th Lines - Address of next of kin and on the 5th line and to the right an initial indicating the soldier's religion. In 1944 the next of kin details were discontinued because it was thought that they gave the enemy information. The seven or eight digits of the soldier's identification number on the second line were broken down as: first two indicate an area within the states, second two town, and last four identify the soldier himself.