I found a Coleman/Marlboro light in my closet. It looked like it held a 6v battery but when I opened it, it had 4D batteries in 2x2. What bulb would give me the brightest light? Its PR based. I tested the batteries with a Radio Shack battery tester (22-091) and it all checked good. But it really yellow and my UK 2L thats been used for about 2 hours is still brighter than this thing. Id like to go get a bulb by 9 pm tonight.