2g Ceramic Tube Ozone Generator KHT-2GD24 (DC 24V) for Air and Water Treatment is a very good unit for big ozone machines or fields below. Open type transfomer. One set includes one ozone tube and one transformer. DGOzone Ltd. and DHL have a direct and strategic cooperation. 60% OFF via DHL Express Shipping. This will make all buyers benefit from low shipping cost. Meanwhile, other shipping ways are available such as FedEx, UPS, TNT, EMS, China Post or Sea. Just let us know which one is best for you, we do all the left work.