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.
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 a full-round action.
Special: If you have the Nimble Fingers feat, you get a +2 bonus on Open Lock checks.
Untrained: You cannot pick locks untrained, but you might successfully force them open.
The character can open locks more quickly than normal.
Source: SRD 3.5 Combined Skills