A pre-filter, reverse osmosis filter, and post-filter will guarantee safety and clarity in your water by removing: Chlorine, Limescale, Bacteria or even Oestrogen. This non-electric filter system is independently certified to NSF standards. The K5 Pure has a flow rate of 3.75 l/min. This means that clean, filtered water will be constantly available. The K5 Pure water filter system gives even purer water than bottled water at only five pence per litre.