The whole bulb is about 13 inches the thicker part is about 5.5 or 6 depending on how you count the flair.
These are rated at 300 watts per inch and calculated at 6 inches. I'm familiar with most of the uv finishes and this rapidly cures them all.
Hard to say hours, there is no counter on the machine. Still strong and powerfull.
Mark is correct about 75.00 to 125.00 if you have to replace bulb.
They are no longer made by American Ultra Violet, so a direct replacement is hard to price. The other light companies don't like to post prices, but you are looking several thousand. When unique sold their UV system, it went for something like 10,000.00
You can check prices with these 2 companies. http://www.uv3.com/products/mobile-handheld-uv/uv-4xl