So, just who is Vault Boy? And what are the true Fallout origins of this symbol and his thumbs-up? Here’s what the Fallout series revealed about Vault-Tec’s emblematic mascot. But thanks to ...

which is the same Vault used in the Fallout TV series. This Rule of Thumb shirt combines the memorable Vault Boy character with the Vault-Tec emblem, which is trademark Fallout at its finest.