Locksmith I: Improves your chances of forcing locks by 10%.
Locksmith II: Improves your chances of forcing locks by 25%.
Locksmith III: Improves your chances of forcing locks by 45%.
Locksmith IV: Improves your chances of forcing locks by 70%.
Locksmith increases your chances of forcing a lock, saving you time opening Treasure Chests and locked doors. Note that forcing a lock will always break a lockpick, and does not earn you any experience or advancement in the Legerdemain skill line.
Tanlorin's Finesse (obtained by having Tanlorin as your active companion, or receiving the Garland Ring Humming Pick upgrade by maxing out their Rapport and level), grants a flat 5% increased chance to successfully force a lock.