Anyone Have Experience With The Raytech Versalume UV Lamp?

I just bought a Raytech Versalume longwave/shortwave UV lamp for checking tagging and repairs, and I cannot tell if I just got a bad unit/bulb, or if these really are THAT horrendous as UV lamps.

The model I got is PP-FLS (item 10020), that is both longwave and shortwave UV, and uses either 4 AA batteries or an AC adapter (included).

I'm completely underwhelmed. Sitting in a completely pitch black room, I have to hold the lamp no more than an inch away from the stamps, and it just gives a barely-discernable overall illumination. No discernable highlighting on UV tagged stamps at all, either US or Canadian.

What gives?