Written separate comments already.
[1] please note correct facts. This one is a water filtration system based NOT on R.O. but U.F. ie ultra filtration. This is the only technology that does not require electricity to make water free of bacteria and virus, Works in absence of electricity.
[2] The product is excellent, I am using it myself for last 22 years now. B.A.R.C. has since come out with U.F. technology filters at less than half of the cost.
[3] Permionics is originally English company known for polymeric membrane products.
[4] Cleaning pre-filters DAILY is a MUST for ANY water filtration system. This is the problem with most consumers, whatever the type of water purifier they use.
[5] In case of failure to so maintain, UF membrane gets exhausted quickly. Flow is reduced BUT never gives impure water. Membranes get choked and are expensive to replace.
Whereas in case of UV light, you will be under illusion of drinking pure water BUT actually full of virus and bacteria.
Both parts of this statement are based on scientific evidence, experienced myself.
[6]Hardly requires any service; but when needed it is difficult to find the technician. Membrane filters are expensive but I changed it when water flow was nil, say once in 5 years.
[7] Pre-filter knob is the only delicate part.