if you want it to work, when you need it, they way you expect get the new ARC AAA P UV. for useability- being there when you need it- the AAA size can't be beat. for about the same $$$, you could also consider the Inova X5 UV. it takes CR123 cells. with UV light the quality of the LED is more noticable. It doesn't pay to get a cheap UV LED if you have a serious need for UV lighting. For less than $40 for either light it's an outstanding value IMHO