This plugin contains two .esp files. The main one you will use is "Ultraviolet Arrows.esp". This plugin adds a number of ultraviolet arrows to shops across Vvardenfell. These arrows are retextured - they glow in the dark and are generally quite shiny :-). They will not do anything special when fired normally.
When in the presence of vampires though, these arrows will do area effect UV damage - quite lethal to vampires. [Note: the scripting on the arrows will make them do area effect damage whenever a vampire is nearby, not just if you aim at one!]
The second esp file is "Ultraviolet Arrows - Vampire Realism add-on.esp". You should use this IN ADDITION to the first if you use Vampire Realism, otherwise any vampires added by Vampire Realism will not be affected by the arrows.
WARNING! This mod uses the EXTRA SPELL from the Construction Set to add new spell effects. This means that it will be INCOMPATIBLE with any other mod that uses this. It probably wouldn't cause any major problems - you'd just get my pretty UV effects instead of the spell effects of the other mod!