The MicroFilter Bottle Set is literally safety in a bottle. To use simply unscrew filter, fill with water from tap, pond or river, re-install filter and hydrate away. Filter alone can be used as a straw allowing drinking directly from water source. Weighing in at only 2.7 ounces, unnecessary weight won't even come into the equation. This chemical free filtration system will still be your safe drinking companion hundreds of liters later.