There are 3 Imp rings. One burns into two when it fails its save versus use. Two burns into three. Three burns into schmada.
In the Original game, you would find a Ring of Life (on SR ten) that when -U-sed would change your con by +2. It would auto-burn into a Ring of Life that had no powers when -U-sed, but was otherwise identical to the Ring of Life you would find on TEN. In that version, all stats maxed at 31, and running around on lvl 10 with a 29 con was highly inadvisable. So If you got drained you could eat your ring.