| 1d20 | Type of Lock | Open Locks % | | :---: | ------------ | :----------: | | 1-6 | Very Simple | +10% | | 7-11 | Average | 0 | | 12-15 | Good | -5% | | 16-18 | Strong | -10% | | 19 | Very Strong | -15% | | 20 | Foolproof | -25% |