+15/-1

Meaning
+15/-1 refers to weapons, such as Amiresh's Piety, that give +15 energy and -1 energy regeneration.

Usage
Using this modifier as your standard weapon set can result in your having no energy, especially if you have no energy management. However, it is common practice for players to keep a seperate weapon set, consisting of a 15/1 wand and 15/1 focus, quickly swapping to that set when they suddenly require extra energy (ie. to gale somebody using resurrect)