The safest distance between two points is a shadowy line.”
Bobblehead - Sneak is a Fallout 3 item, a Vault Boy bobblehead. It permanently improves the Lone Wanderer's Sneak skill by 10, to a maximum of 100. In Fallout 4 it permanently decreases the chance to be detected by 10%.
Found in the yao guai den in the yao guai tunnels on top of a metal box north-east of the big irradiated pool of water, reached by heading down the north tunnel, and through a door.