Poshan Stainless Steel Tiffin Box is one of the most common materials that is preferred for lunch boxes, followed by food-safe plastic. It is one of the best and most effective ways to keep food safe until lunchtime. Poshan Stainless Steel Tiffin Box is much more portable and lighter in weight than the glass versions. This makes them durable enough and easier to carry around whether heading to school or to an office. These can be heavier and could weigh you down.