Tri-Test Multifunction Counterfeit Detection Machine uses the latest in Ultraviolet LED technology to provide the ultimate in security against counterfeit currency INCLUDING WASHED BILLS. UV LED''s detect the UV sensitive security thread in US currency in denominations of $5 and larger. Use the original Counterfeit Detector Pen to test the paper, the UV LED''s to reveal the UV security thread, and backlight the bill with the white LED''s to reveal watermarks and micro-printing. Versatile unit also authenticates drivers'' licenses, passports, international currencies, credit cards, cashier''s checks, and more. The Tri-Test is a powerful, compact, portable and affordable solution for any point of sale application. A must for bars and restaurants that check ID''s and payment methods. LED''s last for years and are powered by 3 AAA batteries (not included).