The filter can be used for a full year or 4700 litres, which ever comes first, without having to do any maintenance. When you divide the S$1000 over the 4700 litres of water, it only cost you S0.21 cents per litre of clean drinking water for the 1st year, subsequent S$0.06 cents/litre. Where can you buy outside stores at this price. At the supermart, it cost you at least $1.00 for maybe 500g of water. Why waste your money and save the Earth at the same time. The plastic bottles are not safe, especially when exposed to the sun, the toxins leak into the water.
It can remove 99.9% of the unwanted toxins like Chlorine, lead, mecury, bacteria and viruses because it can filter to as small as 0.20 microns (i.e.500 times smaller than a strand of your hair) The UV lamp will neutralise the bacteria and virus.