5 pack blacklight 

405nm violet LED

The MEL-BL (Micro Effects Lights, Black Light) is used to stimulate fluorescent material in props, scenery and art. The LED light can be un-plugged from the battery clip harness. The LED light uses a DC barrel connector of the 2.1mm x 5.5mm size. The MEL-BL can also be operated from 12 volts DC providing slightly higher output but with diminished life. The LED blacklight DC barrel connector is center positive. The 405nm LED output is at the violet range of the spectrum, the lower regions of the visible light just outside of true the true UV-A region. The 405nm blacklight works well with many fluorescent paints in prop, scenery, and art applications. The operating life from a new 9V battery can be expected to be greater than 12 hours.