This magical instrument adapts itself to the ethical disposition of its possessor, so it will produce either a Good or an Evil effect depending on the alignment of its owner. If the possessor is absolutely Neutral in ethical alignment, then the horn will have no power whatsoever. 

If the owner is Good, then winding the horn has the effect of a protection from evil spell in a 10-foot radius, and this protection will last for 10 rounds. Each friendly/allied creature within this area will be affected as if he or she was granted the spell. 

If the horn is of Evil alignment, then the reverse of the noted spell occurs within the area of effect. 

The horn can be blown but once per day.