The new Stanley Gibbons Detectamark Spectrum makes it easy to discover the hidden rarities in your collection. It's multiple colour settings and adjustable light source, are unique to the Detectamark Spectrum & provide additional help when identifying more difficult watermarks. It even shows up watermarks on modern stamps printed on thick, chalk-surfaced papers with full gum – the ones that other detectors fail to identify. It is clean, safe and very effective, without the use of chemicals and solvents and also helps to detect minor damage, such as thins, tears or repairs. The Detectamark is constructed from durable lightweight plastic and battery operated, so ideal for taking to exhibits and meetings. Requires 4 AA batteries (not included).