Open Locks

Open lock, like the name implies, opens locked chests and doors. It consumes one Thief tool per attempt, whether or not the unlock was successful. Unlike disarming traps, there is no chance of damaging the lock and making the chest/door unusable. You can repeat as many times as you like as long as you have tools left.

Sidenote: Sometimes there are keys for locked doors and sometimes there aren't. Know which door has a key can save you a reagent and bring your team closer to the experience bonus for killing mobs, as most keys are surrounded by monsters usually.