This kit is identicle to the reverse osmosis kit above but uses the RO Ultratec HF4-4040 membrane instead.This membrane is made under licence from FilmTec and is almost identicle to the FilmTec XLE-4040 membrane. In terms of performance compared to the Osmonics AK4040 it will produce slightly less water but of a slightly higher quality - i.e less flow rate but with lower product TDS. People who bought this item also bought: