We use Crypopaks from Restaurant Depot. They are a reusable gel pack that work much better than ice, but we have found that they work much better when placed in a quart sized ziploc. The gel packs are susceptible to tears after a few uses, so placing them in ziplocs gives them a longer life span. These things get seriously cold, and last way longer than ice.
CBJ, 15' custom BBQ trailer with a Backwoods Competitor, Pitts & Spitts off-set, & Santa Maria grill. Ole Hickory CTO, 1 BGE, 2 Weber kettles and 1 Smokey Joe, BWS Chubby, Sonoma gasser, and a BBQ store full of everything BBQ.