Advanced, roto-molded polyurethane armor protects a core of foam that averages 2.00”+, all of it working in tandem with a heat- cheating gasket in the lid to create an internal environment that is very slow to change. Very slow.
Throwing ice into a warm cooler accelerates thaw. Throwing a case of warm beer into your cooler on top of ice is another energy drain/ice melter. Chilled contents, into a chilled cooler is the way to maximize ice retention. Without access to a walk-in cooler (or cold weather), a sacrifical bag of ice is the best way to pre-chill.