Aftermarket 6 stage replacement filter pack. Will fit the Envirotec(R) ET6500 and other reverse osmosis systems that require a 1 micron sediment pre-filter, a 1/2 micron carbon pre-filter, an ECT post-carbon filter, a 5 micron GAC post inline filter and a calcite (mineral enhancer) post charger. The 6th stage filter charges the purified water with benificial minerals. Includes a 1 micron sediment filter, a .5 micron Carbon block filter, a ECT post-carbon filter, a GAC post filter(inline) and a Calcite post charger. Includes the service manual “How to Service Your Reverse Osmosis System” by Dionicio Porras.