Includes the following standards:NSF 42-2007e:Drinking Water Treatment Units - Aesthetic EffectsNSF 44-2007:Residential Cation Exchange Water SoftenersNSF 53-2007a:Drinking Water Treatment Units-Health EffectsNSF 55-2007:Ultraviolet Microbiological Water Treatment SystemsNSF 58-2007:Reverse Osmosis Drinking Water Treatment SystemsNSF 62-2004:Drinking Water Distillation SystemsSave over $100 when buying this set!