The O3Elite Dual Ozone Generator has a number of important features that make it one of the best in the world: Universal voltage – use it anywhere in the world without a step-down transformer Dual quiet, efficient ozone cells – ultra pure ozone without the noise created by other machines Ceramic ozone cells – just as ozone resistant and ultra pure as glass but without the potential burnout. Luer lock connections – tubing locks on securely with no slip Cold ozone production – no heat that degrades the ozone; cold corona; no need for cooling fans Ultra pure ozone is created using very low voltage, which is safer for you, up to 110 ug/ml CE approved Independent cells – run individually or together for more options Made in the USA – all parts are manufactured in the US and units are thoroughly checked by hand before shipment