Lock & Lock insulated picnic set (exploded view)

Closed-up view of the bag is here. The bag is lined with insulated material so you can pack a gel pack along with your picnic for food safety. There are three Lock & Lock 870ml food containers inside (one fitted with four smaller food cups), so this is the right size for a multiple-person picnic. I picked this up for US$13.50 at Kamei (on Clement St.) in San Francisco. (EDIT: Evidently Target sells the individual box with four smaller sub-containers for US$3.96.)