All the coolers we've recommend above are capable of holding things at a safe temperature for a day, provided you keep them in the shade. Rotomolded coolers offer seamless, uniform density in their walls and lids, which drastically improves a cooler's performance. In contrast, those ancient, affordable plastic coolers we've all used have thinner walls, leaky seams, and less insulated lids. Soft-sided coolers: Soft-sided coolers include everything from well-padded, impressively insulated sling bags (like the Yeti Hopper Flip above) to roll-down, dry-bag-style coolers perfect for those mild beach days. The best soft coolers are easier to carry, pack away easily when not in use, and have a versatility that traditional hard coolers lack.