We reviewed the 2019 backpack coolers from YETI, OtterBox, Hydro Flask, and more to find out which is best. Read our take on ice retention, portability, and cooler features. In 2019, cooler brands big and small invested in developing backpack models. Cooler backpacks haul ice, beer, and food easily to the campsite, park, or hiking trail. But each cooler comes with advantages and disadvantages. In our test, we discovered ice retention isn’t everything. With cooler backpacks, key attributes were portability and comfort. When you load an entire backpack full of ice, water, and beer, it gets heavy quickly. Caveat: There wasn’t one clear winner in this review, and the brands aren’t listed in any particular order. But each cooler succeeded in certain areas. We’ve organized this review with modules detailing each product, noting where each excelled and lagged. The YETI Hopper BackFlip 24 is a rugged, well-built cooler with lash points on all sides. It sports one central zipper, YETI’s beefy HydroLok — which we’ve tested before, and it didn’t break or leak. And it makes the BackFlip waterproof. YETI’s DryHide shell is on the outside. It withstands abrasions well, didn’t rip in our field...