The archetypal tool to detect phosphor papers and inks for the majority of the 20th Century Machin stamps of Great Britain, Israel, USA, Finland and the early phosphors of , Norway, Mexico, France, Hong Kong, People's Republic of China, Russia and later issues of Canada and Mexico.

The lamp has a spectrum of 254 to 390 nm (nanometers) and therefore covers both "short" and "long" wavelengths.

Requires 4 x AAA Batteries, Not supplied.