This guy should be able to point you in the right direction for a good cob.
@BigSm0
Not all cobs are created equal. Most cob lights sold on eBay have no benefit over leds on eBay. Basically what I'm saying is cob isn't some miracle light that will triple your yields. What can increase your yields is more efficient lighting and specific cobs like Cree and citizen are the most efficient (light per watt) cobs available. They also have a more full or complete spectrum which plants really need. The price per cob complete is not cheap but the benefits, growth, grams per watt, energy consumption, lower heat, ext is pennies in the long run.