Four Leaf Clover

Four Leaf Clover is a perk in Fallout 4.

Effects
The first rank of four leaf clover adds a 7.5% chance of earning a critical for every shot in vats. For every rank after that it adds an extra 2% upto a total of 13.5%.

Behind the scenes

 * Vault Boy's outfit and fighting stance in the perk icon are a reference to the University of Notre Dame's mascot, the Fighting Irish