BergHOFF's trolley freezer bag is designed to fit into bag one of the trolley bags original size set. The bags roll up neatly with a velcro handle to take into the supermarket. The stay cool bag folds in thirds and secures with velcro straps. This insulated bag will keep all your cold items cold longer. This ensures that wherever you're going, this bag is sure to keep your frozen or cold items cool and/or frozen. The cool bag can be zipped up and removed from the trolley with bag 1 handles. After use, the trolley cool bag can be easily folded back up, ready for your next shopping trip.