This versatile ink pen is a RF and UV Detection Device. The pen automatically detects wireless signals and alerts you with a red flashing light at the tip of the pen according to signal strength the flashing will be more frequent. Push the button on the side of the pen to illuminate the UV light to check for counterfeit currency by detecting the water mark. You'll never have to worry about turning the pen on to detect a signal it is always on detecting for you. Specifications: • Automatic RF detection • Built-In anti mobile phone interference • Frequency range 100MHz to 3GHz • Currency checker • Functioning Ink Pen • Detects a radius of 1-10 meters • • Precisely detect wireless signals of • 900/1200/1300 and 2400/2600/3000MHz Includes: • RF/UV detection pen with case • 4 sets of batteries (battery life approximately 4 weeks depending on use) • Instructions SIZE: 5" x 2-Jan" x 0"