The document discusses different types of water ionizer machines, which use electrolysis to separate tap water into alkaline and acidic water. It explains that water ionizers work by passing electricity through tap water in an ionization chamber, with the positive terminal producing acidic water and negative terminal producing alkaline water. The document also lists some common types of water ionizers like countertop, undercounter, and portable models, and describes some potential health and household uses of ionized alkaline and acidic water.