These are pre-cut, ready to use insulation sheets and wraps made of twin-wall metallized temperature-resistant co-polymer. We include these with our Pro-Line series of pans but offer the kits separately on all of our pan sizes.
The bottom line is that the larger your pan the more you will benefit from insulation. Yes, heat loss through plastic is less than through a metal pan but it's still significant. Depending on time of use and temperatures your insulation kit will reduce energy consumption by up to 50%, provide faster heat-up time and allow you to reach and maintain higher temperatures needed for tougher meats and vegetables especially with the large capacity tanks.
What about coolers?
Most people think of an insulated sous vide pan as an ice chest (cooler) with a notch cut in the top. One problem is obvious in that this ruins a perfectly good cooler :( Another problem is less obvious but logical: ice chests are made to keep food cool, not hot. The inside shells are typically made of plastics with much lower softening temperatures than polycarbonate (polypropylene, for example) so distortion can occur at higher sous vide temperatures.