2 of 2 people found the following review helpful
UV Pen Review,
This review is from: Compact Pro Permanent Ultraviolet Marker Pen (Office Product)
I bought 3 types of UV lamps and this UV pen to compare.
The pen is clearly visible under UV, but it is also clearly visible under normal light as it leaves a very glossy marking. It is not really covert as you can always see it...