Open Lock Skill

Open Lock (Dex; Trained Only)
Attempting an Open Lock check without a set of thieves’ tools imposes a –2 circumstance penalty on the check, even if a simple tool is employed. If you use masterwork thieves’ tools, you gain a +2 circumstance bonus on the check.

Check
The DC for opening a lock varies from 20 to 40, depending on the quality of the lock, as given on the table below.

Action
Opening a lock is an action.

Untrained
You cannot pick locks untrained, but you might successfully force them open.