Keep’N Box The Keep’n box storage boxes are a sustainable alternative to single-use plastic products. The range is ideal for keeping your food fresh, in the fridge or freezer. It is also microwave safe. Keep’n Box is suitable for everyday use: stackable to save space. The range is available in square, rectangular and round formats. It adapts to every need with its nine different capacities. Keep’n box also includes a jug, a jar, a ham box and salad bowls.