Tundra 35 Cool Box

YETI's PermaFrost insulation is pressure-injected polyurethane foam packed into the walls and lid of the cooler. Filling the space completely leaves fewer gaps for heat to get through, so ice lasts longer on camping trips, days on the water and anywhere the cool box sits out in the sun.

FatWall is YETI's extra-thick wall design, built to hold up to three inches of pressure-injected insulation. More insulation between your drinks and the outside world means the cold holds for longer, which is what lets these coolers keep ice through a warm weekend away.

The ColdLock gasket is a moulded rubber seal that runs around the rim of the lid. When the lid closes it presses into place to form a tight thermal barrier, sealing cold air in and warm air out so the contents stay chilled far longer than in an unsealed box.

YETI's InterLock lid system is shaped so the lid and body fit closely together when shut. Working with the gasket it creates a consistent seal around the whole opening, cutting the heat transfer that would otherwise melt your ice through the gap where lid meets base.