I would HIGHLY suggest ReptileBasics.com for the flexwatt you need instead of using ebay. Rich there has been dealing with the stuff for a long time and his customer service is 2nd to none. He will cut it and attach all the connections for you for free. I buy all my flexwatt for my incubators/racks from RBI and have never had a problem.
His Flexwatt FAQ:www.reptilebasics.com/flexwatt-faq.html