The dimensions are: 1" tall x 1" wide x 3/32" thick. The chain is the beaded "dog tag" type. Image available for licensing.
NEVER AGAIN = HOLOCAUST = NEVER AGAIN
The design consists of an octagon shaped background which represents a “stop” sign, the NA for NEVER AGAIN, and the Magen or “Star” of David, which is not only the national icon of the State of Israel but also symbolic of the “yellow” star worn on the clothing of, and used to identify Jews, during the Holocaust.