Check every attack by dicing a d10 along with the d20 (or a d10 along with a saving throw). A 1-2 on the d10 indicates malfunction and loss of protection for that attack or save.
The saving throw granted for disbelieving and illusion is a regular saving throw, so a ring of protection does grant its bonus to such saves.
The rules give a range of 2,000-4,000 XP and 10,000-20,000 GP, but do not indicate precise values for each ring type.
The following table can be used:Ex
| Ring | XP | GP |
|---|---|---|
| +1 | 2,000 | 10,000 |
| +2 | 2,500 | 12,500 |
| +2, '5 radius | 3,000 | 15,000 |
| +3 | 3,000 | 15,000 |
| +3, 5' radius | 3,500 | 17,500 |
| +4 | 3,500 | 17,500 |
| +6 | 4,000 | 20,000 |