Small enough to fit in a shirt pocket or glove compartment, the 40-20 UV light is always handy when you need it. The end mounted suction cups allows for full use of the 6" UV bulb. The 40-20 UV light runs on AA batteries so no additional power source is required. Not intended for primary use but makes a great back up or second UV light. Replacement Bulb: 40-2B or 40-2W.