Amazon is selling a 'perfect size' $40 cooler backpack for $21, and shoppers say it has 'room for everything'

TheStreet aims to feature only the best products and services. If you buy something via one of our links, we may earn a commission. Amazon has a cooler backpack on sale right now that is great for all your summer activities. Whether you're hiking, camping, or spending the day at the beach, the…