People in need of a modest amount of refrigeration or warming should check out the line of portable systems from Cooluli. For example, the company’s Classic 4L model has a 4.0-liter capacity (4.2 quarts), which is enough to chill up to six 12-ounce beverage cans, your lunch bag, or anything else that’s best kept cold. The unit, which also warms, includes both AC and DC power cords so you can plug into your vehicle or at home, and it has a USB charging cord that attaches to an external power supply. The Classic 4L costs $50, but Cooluli also sells larger units available at prices ranging from $80 to $150. To order, head to www.cooluli.com.