Longevity's "All Digital" NEOS™ Technology and 100% Quartz Glass Electrode provides spectacular (and proven) Purity, Precision, Quality and Reliability. Proven high Quality comes to you in the form of QAI Certification to CSA and UL Standards, independent testing performed by QAI - "Quality Auditing Institute Laboratories". Longevity's CE Approval provides the Proof of Quality required by European customers. You should only ever have to purchase one ozone generator in your lifetime. The EXT120 and EXT120-T will provide you with that Lifetime of use. We've proven it.