This is an electrolytic hydrogen water machine from OSG Corporation. I received it about 10 years ago. There is some yellowing due to age. Water types: * Raw water (for washing dishes, etc.) * Hydrogen water (for everyday drinking) * Purified water (for medicine and making baby formula) * Acidic water (for washing your face) It's really convenient because you can switch between the water types by pressing levers and buttons☆ The cartridge needs to be replaced once a year, and it costs about 12,000 yen. You will need to order and have the cartridge installed by OSG. With a phone call, an OSG representative will come directly to replace the cartridge and perform a concentration test and maintenance each time. It's easy to install, just attach it directly to the faucet. The hose is also available for replacement (for a fee), so if you are concerned, please consider replacing it when you install the machine! No claims and no returns, please.